Pure line in homogeneous population
(A): Occurs in self-pollinated crop. (R): These are progenies of a single self-fertilized individual.

Correct option is A

Pure lines are genetically uniform populations. They are commonly found in self-pollinated crops.
Pure lines originate from repeated selfing of one plant.
Hence all progenies are genetically identical. Reason correctly explains the assertion.
Therefore option (a) is correct.