A
A is correct for this problem
Answer:
The most appropriate answer would be option B.
The flaw in their reasoning is that they compared different molecules in a different set of organisms.
For example, they compared the DNA of lizard A and B whereas they compared the RNA of lizard B and C.
In addition, the mutation rates of different molecules (DNA and RNA) are different and thus, comparison of DNA in one set of organism and comparison of RNA in another set cannot be used as the basis for the conclusion.