CDNA Libraries from Liver Cells Are Different Than CDNA Libraries

Multiple Choice

cDNA libraries from liver cells are different than cDNA libraries from kidney cells because

A) the DNA is not the same in the two types of cells.
B) reverse transcriptase acts differently in the two types of cells.
C) mRNA is different in the two types of cells.
D) polyA is present at 3ʹ ends of mRNA in one cell type only.