**Cell Cycle and its Phases**

The cell cycle is the process by which a cell grows, replicates its DNA, and divides into two daughter cells. It consists of a series of events that occur in a specific order and are tightly regulated to ensure the proper growth and division of cells.

The cell cycle can be broadly divided into two main phases: the interphase and the M phase (mitotic phase). Let's discuss each of these phases in detail:

**1. Interphase:**
- Interphase is the longest phase of the cell cycle and accounts for about 90% of the total cell cycle duration.
- It is further divided into three distinct phases: G1 phase, S phase, and G2 phase.

**a) G1 phase (Gap 1 phase):**
- G1 phase is the first phase of interphase and is characterized by cell growth and metabolic activities.
- During this phase, the cell prepares itself for DNA replication by accumulating energy and synthesizing proteins required for cell division.

**b) S phase (Synthesis phase):**
- S phase is the second phase of interphase and is characterized by DNA replication.
- The cell replicates its entire genome to ensure that each daughter cell receives a complete set of genetic information.

**c) G2 phase (Gap 2 phase):**
- G2 phase is the last phase of interphase and is characterized by further cell growth and preparation for cell division.
- During this phase, the cell synthesizes proteins and organelles required for cell division.

**2. M phase (Mitotic phase):**
- The M phase is the second main phase of the cell cycle and involves the actual division of the cell into two daughter cells.
- It is further divided into four distinct phases: prophase, metaphase, anaphase, and telophase.

**a) Prophase:**
- Prophase is the first phase of the M phase and is characterized by the condensation of chromatin into visible chromosomes.
- The nuclear envelope breaks down, and the mitotic spindle begins to form.

**b) Metaphase:**
- Metaphase is the second phase of the M phase and is characterized by the alignment of chromosomes along the equatorial plane of the cell.
- The spindle fibers attach to the centromeres of the chromosomes.

**c) Anaphase:**
- Anaphase is the third phase of the M phase and is characterized by the separation of sister chromatids.
- The spindle fibers contract, pulling the sister chromatids towards opposite poles of the cell.

**d) Telophase:**
- Telophase is the last phase of the M phase and is characterized by the decondensation of chromosomes and the reformation of the nuclear envelope.
- The cell begins to divide, leading to the formation of two daughter cells.

**Conclusion:**
The correct answer is option 'A' - a cell cycle includes interphase and the M phase. Interphase is the phase where the cell grows and replicates its DNA, while the M phase is the phase where the cell actually divides into two daughter cells through the process of mitosis. The other options mentioned (b, c, and d) represent different phases or processes within the cell cycle, but they are not the complete cell cycle itself.