Carl's Genotype Is Heterozygous for a Specific Discrete Trait

Multiple Choice

Carl's genotype is heterozygous for a specific discrete trait.What does this say about Carl's phenotype?

A) The trait will not be expressed in his phenotype, but he will pass it on to his children.
B) The trait will only be expressed in his phenotype if he has the proper environmental exposure during his critical period.
C) If the trait is dominant, it will be expressed in his phenotype, but if it is recessive it won't be expressed.
D) The trait will be expressed in his phenotype.