Let $a, b, c$ be regular expressions. Which of the following identities is correct?
Correct Answer: $D$
a. not contain ba string in rhs
b. not contain ac string in rhs
c. RHS contain only string containing no of a's or no of b's only
Above all are not equal.
d. It is correct because LHS string of ab or a ending with a is equivalent to a followed by ba or a. Both Regular expression produce palindrone of odd length start or end with a and another string containing any no of a's string.