Answer
Being that the wrinkled phenotype is recessive and the pea plants are diploid, both the chromosomes used to make the offspring plant were homozygous recessive.
Work Step by Step
The wrinkled phenotype is recessive. The pea plants self pollinated, and all three plants had wrinkled peas. This means that the peas have no dominant alleles whatsoever, and could not produce round peas. As the wrinkled phenotype is a loss of function mutation, this means that the peas all carry the mutation and are all homozygous recessive.
