Pure line is the progeny of

Answer: Option D

The pure line is the progeny of the nucleus seed.
Pure-line selection involves selecting and breeding progeny from superior organisms for several generations until a pure line of organisms with only the desired characteristics has been established.
Nucleus Seed is the initial amount of pure seed of improved variety or parental lines of a hybrid produced under the supervision of the plant breeder who has evolved that variety or hybrid. The nucleus seed is genetically cent percent pure and does not contain other physical impurities.