If the chromosome number in the root cell of Zea mays (maize) is 20. Then what would be the chromosome number in the cell of radicle (a), hypocotyl (b), epiblast (c), aleurone layer (d), and scutellum (e) respectively?

The correct option is D a = 20; b = 20; c = 20; d = 30; e = 20
Zea mays is diploid $\left(2n\right)$ so value of$n=10$.

Ploidy of radical, hypoblast, epiblast and scutellum is diploid whereas aleurone layer is triploid.

Therefore, number of chromosomes in radical hypoblast, epiblast and scutellum becomes $20(2n=2\times 10=20)$ and aleurone layer will have 30 number of chromosomes $(3n=3\times 10=30)$.

So, the correct answer is "option B"