Which best describes the factors that affect a phenotype?

Genotype and the environment both can affect a phenotype.

Phenotype = a physical feature resulting from a certain genotype.

For example, let's say a person born with a genotype pp has the phenotype: pale skin. However, if they live in a sunny environment, then the melanin in their skin will increase over time changing their phenotype to tan skin. Does that make sense as to how both factors can impact phenotype?