Which of the following statements is correct?

Mendel's pea plants could cross-fertilize but not self-fertilize.

A genetic cross produces the P generation.

True-breeding plants are able to produce a variety of flower colors when self-fertilized.

Offspring of two different true-breeding varieties are called hybrids.

Offspring of two different true-breeding varieties are called hybrids.

Explanation:

Pure-breeding plants are plants that self pollinate for many generations and all its offspring had the same features as the parents, generation after generation.

When Mendel cross pollinate this pure-breeding plants with contrasting traits, the offspring is called hybrids because they resulted from a cross between two pure-breeding plants with contrasting traits.