The function of centriole is the formation of spindle fibers during cell division. Centrioles are small cylindrical structures found in animal cells, and they play a crucial role in organizing the microtubules that make up the spindle fibers. The spindle fibers are responsible for separating the chromosomes during cell division, ensuring that each daughter cell receives the correct number of chromosomes.

Here is a detailed explanation of the function of centrioles in the formation of spindle fibers:

1. Structure of Centrioles:
- Centrioles are composed of nine sets of microtubule triplets arranged in a cylindrical shape.
- Each triplet consists of three microtubules arranged in a circular pattern.
- The two centrioles within a cell are usually located near the nucleus and are oriented perpendicular to each other.

2. Centrosome Formation:
- The two centrioles together with surrounding proteins form a structure called the centrosome.
- The centrosome serves as a microtubule organizing center (MTOC) in animal cells.

3. Spindle Fiber Formation:
- As the cell enters the stage of cell division called mitosis, the centrosome duplicates itself.
- The duplicated centrosomes move to opposite sides of the nucleus.
- Microtubules begin to extend from each centrosome, forming spindle fibers that radiate towards the center of the cell.

4. Role in Chromosome Segregation:
- The spindle fibers attach to the chromosomes at specific sites called kinetochores.
- The kinetochores are protein structures located at the centromere region of each chromosome.
- The spindle fibers exert force on the kinetochores, pulling the chromosomes towards the opposite poles of the cell.

5. Cell Division Completion:
- Once the chromosomes have been separated, the cell undergoes cytokinesis, the process of dividing the cytoplasm.
- The spindle fibers disassemble, and the centrioles return to their original position near the nucleus.

In conclusion, centrioles play a crucial role in cell division by organizing the spindle fibers required for the separation of chromosomes. The formation of spindle fibers ensures the accurate distribution of genetic material to the daughter cells.

The correct answer is option 'A', which states that the function of centriole is the formation of spindle fibers during cell division.

1. Introduction:
Centrioles are small, cylindrical structures found in animal cells. They are composed of microtubules and are typically found in pairs, arranged perpendicular to each other. Centrioles play a crucial role in cell division.

2. Cell Division:
Cell division is a process by which cells reproduce and create new cells. It is essential for growth, repair, and reproduction in organisms. There are two types of cell division: mitosis and meiosis. Centrioles are involved in both types of cell division.

3. Spindle Fibers:
During cell division, the centrioles migrate to opposite ends of the cell, forming the poles of the cell. They then begin to produce spindle fibers, which are responsible for separating the chromosomes and ensuring equal distribution of genetic material to the daughter cells.

4. Mitosis:
In mitosis, which is the process of cell division for growth and repair, the centrioles replicate before the cell divides. The replicated centrioles move to opposite poles of the cell, and spindle fibers extend from each centriole towards the center of the cell. These spindle fibers attach to the chromosomes and help in their alignment and separation during cell division.

5. Meiosis:
In meiosis, which is the process of cell division for sexual reproduction, the centrioles also play a role in spindle fiber formation. However, the centrioles do not replicate before meiosis II, and only one pair of centrioles is present. The spindle fibers formed by these centrioles help in the separation of homologous chromosomes and the formation of haploid daughter cells.

6. Conclusion:
In conclusion, the function of the centriole is to form spindle fibers during cell division. These spindle fibers are crucial for the proper alignment and separation of chromosomes, ensuring the accurate distribution of genetic material to the daughter cells. Without centrioles, cell division would not proceed correctly, leading to various abnormalities and disorders.