Answer is B because sclerenchyma contains dead cells and it's cell wall are very thick due to the deposition of lignin ..... and it is very hard and stiff and provide rigidity to the plant

The correct answer is option 'B' Sclerenchyma.

Sclerenchyma is a type of plant tissue that provides mechanical support to the plant. One of the characteristic features of sclerenchyma cells is their thickened and lignified cell walls.

Lignin is a complex polymer that is deposited in the cell wall of sclerenchyma cells. It is a hard and rigid substance that provides strength and rigidity to the cell wall. The deposition of lignin in the cell wall makes it thick and tough, allowing the sclerenchyma cells to provide support to the plant.

Sclerenchyma cells are found in various parts of the plant, including the stem, roots, and leaves. They are often present in regions that require mechanical support, such as the outer layer of stems and the veins of leaves.

The thickened and lignified cell walls of sclerenchyma cells make them highly durable and resistant to mechanical stress. They are often dead at maturity and function solely for structural support. The presence of sclerenchyma tissues gives strength and rigidity to the plant, allowing it to withstand external forces such as wind or gravity.

In contrast, collenchyma and parenchyma cells have primary cell walls that are thin and flexible. Collenchyma cells provide flexible support to growing plant parts, while parenchyma cells are involved in various metabolic functions such as storage and photosynthesis. Phloem, on the other hand, is a complex tissue responsible for the transport of sugars and other organic molecules throughout the plant.

To summarize, the correct answer is option 'B' Sclerenchyma because it is the only plant tissue among the given options that has a characteristic feature of thickened and lignified cell walls.