In angiosperms pollen grains are

The right answer is The pollen grain is the haploid male gametophyte,

In seed plants, pollen is the male mobile element produced by the flower: these are tiny grains, more or less ovoid in shape, initially contained in the anther at the end of the stamens.

In certain flowering plants, germination of the pollen grain often begins even before it leaves the microsporangium, with the generative cell forming the two "spermatic" cells.

1. D

2. A

3. C, D

4. D

5. A