Each of the following is a modification of the sentence THE CAT ATE THE RAT. A. THE RAT ATE THE CAT B. THE TAC ATE THE RAT C. THE CAT ARE THE RAT D. THE CAT ATT HER AT A frameshift mutation could result from a a base insertion only. b a base deletion only. c a base substitution only. d deletion of three consecutive bases. e either an insertion or a deletion of a base.