When a pea plant that is homozygous dominant (let's denote it as DD) for a certain trait is crossed with a pea plant that is homozygous recessive (denoted as dd) for that trait, you would expect the following in the F1 generation:
All of the plants in the F1 generation will have the dominant trait (D). This is due to the dominant allele (D) masking the expression of the recessive allele (d).
So, the correct answer is:
OC. All of the plants in the F1 generation will have the dominant trait.