The question asks which of the listed plant tissues is usually without protoplast and comprises dead cells. To answer this question, let's examine each option:

1. Collenchyma: This is a type of plant tissue that provides support while allowing for growth due to its flexible nature. Collenchyma cells have living protoplasts, meaning they are not dead cells.
2. Parenchyma: Parenchyma cells are living cells that are involved in functions like photosynthesis, storage, and tissue repair. These cells contain protoplast, so they are not dead.
3. Xylem parenchyma: These are living cells found in xylem tissue and help in storage and lateral transport of water. Being living cells, they contain protoplast.
4. Sclerenchyma: These cells are specialized for providing mechanical support. Sclerenchyma cells are typically dead at maturity as they lose their protoplast. They have thick lignified walls, making them rigid and non-flexible.

The correct answer is Sclerenchyma, as it is the only tissue listed that consists of dead cells and lacks a protoplast.