Please Use the Following Information to Answer the Question(s) Below

Multiple Choice

Please use the following information to answer the question(s) below.
A man who is an achondroplastic dwarf with normal vision marries a color-blind woman of normal height. The man's father was 6 feet tall, and both the woman's parents were of average height. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is X-linked recessive.
-Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others produce pink flowers. This can be best explained by which of the following statements?

A) Multiple alleles are involved in the expression of the phenotype.
B) The allele for blue hydrangea is completely dominant.
C) The alleles are codominant.
D) Environmental factors such as soil pH affect phenotype.