In angiosperms, pollen grains are

In angiosperms, pollen grains are
a. diploid and are made when haploid gametes join in fertilization
b. diploid and are made when haploid gametophytes join in pollination
c. haploid and are made when haploid spores undergo mitosis
d. haploid and are made when haploid ovules undergo meiosis. i think it’s b but i feel like i’m way off