Which of the following best explains the difference among dominant and recessive alleles?

A. The recessive allele encodes a protein with normal activity whereas the dominant allele produces a protein that functions at even higher levels.

B. The dominant allele forms a protein with normal activity while the recessive allele is either not transcribed or produces a mutant protein that does not function. 

C. The dominant allele is always transcribed at a higher level than the recessive allele therefore the level of protein from the dominant allele is also higher than from the recessive allele.

D. The dominant and recessive alleles produce proteins that have dissimilar functions.