Which of the following is NOT functionally important in cells of the gametophytes of both angiosperms and gymnosperms?

a. haploid nuclei

b. chloroplasts

c. mitochondria

d. cell walls

The correct answer will be option - B.

Explanation:

The gametophyte is the phase of the life cycle of the plant which produces the gametes of the plants.

The chloroplast is the organelle associated with the production of the food in the form of glucose using sunlight and carbon dioxide. The gametophyte is the reduced phase of the angiosperms and gymnosperms which lacks chloroplasts as the gametophyte of these groups directly depends on the sporophyte of the plants.

Thus, Option-B is the correct answer.