Consider this plant cell. which organelle is labeled a? nucleus vacuole ribosome mitochondrion

That is the Vacuole :D

The correct answer would be vacuole.

The vacuole is a membrane-bound cell organelle present in the cytoplasm of the cell.

It serves as the storage site where animal or plant cells store their organic and inorganic material.

For example, in plant cells store water, food material (carbohydrate, amino acids, fats, or minerals), organic acids, ions et cetera.

In plants, vacuoles help in maintaining the turgidity and rigidity of the cells. It is the reason that the size of vacuoles is larger in plant cells as compared to the animal cells.

It can occupy up to 50-90 percent volume of the plant cell.