Collenchyma cells mainly form supporting tissue and have irregular cell walls. They are found mainly in the cortex of stems and in leaves. The major function of sclerenchyma is support. Unlike collenchyma, mature cells of this tissue are generally dead and have thick walls containing lignin.

Collenchyma is the tissue that meets the given characteristics.

Introduction:
Plant tissues are classified into different types based on their structure, composition, and function. Collenchyma is one of the three types of simple permanent tissues in plants. It is a living tissue that provides mechanical support to the plant.

Characteristics of Collenchyma:
Collenchyma cells possess the following characteristics:
1. Living Cells: Collenchyma cells are living cells that are derived from meristematic tissues.
2. Angular Wall Thickening: The primary cell walls of collenchyma cells are thickened at the corners, resulting in angular cell shape.
3. Elongated Cells: Collenchyma cells are elongated in shape and may have unevenly thickened walls.
4. Mechanical Support: These cells provide mechanical support to the plant organs and help in resisting bending and stretching forces.

Explanation:
Based on the given characteristics, the tissue described is collenchyma. Let's analyze the other options to understand why they are not the correct answers:

Xylem: Xylem is a complex tissue responsible for water and mineral transport in plants. It consists of several cell types such as tracheids, vessel elements, fibers, and parenchyma cells. While fibers in xylem provide mechanical support, they do not show angular wall thickening, which is a characteristic of collenchyma.

Epidermis: Epidermis is the outermost layer of cells in plants. It serves as a protective barrier and helps in preventing water loss. While epidermal cells may have thickened walls, they do not exhibit angular wall thickening, which is a characteristic of collenchyma.

Sclerenchyma: Sclerenchyma is another type of simple permanent tissue that provides mechanical support to plants. It consists of cells with thick, lignified secondary cell walls. However, sclerenchyma cells do not show angular wall thickening, which is a characteristic of collenchyma.

Therefore, based on the given characteristics, the correct answer is option A) Collenchyma.

Refer to ncert page no.86 collenchyma paragraph line no..4&10