Statement-I : Mass numbers of most of the elements are fractional.
Because
Statemen-II Mass numbers are obtained by comparing with the mass number of carbon taken as 12.

Options

A. If both (A) and (R ) are correct and (R ) is the correct explanation for (A).
B. If both (A) and (R ) are correct but (R ) is not the correct explanation for (A )
C. If both (A) and (R ) are incorrect.
D. If both (A) and (R ) are incorrect.

Answer

D