L={WWR∣W∈{a,b}*}.
This Language accepts Even length of palindrome.
The set of strings generated by L ={∈,aa,bb,abba,baab,bbbbbb,bbaabb....}
(A)Due string ab(S->aSb->ab) we can eliminate this option because this is not even length palindrome.
(B)In this option accepts all even length palindrome. Ex:-∈,aa,bb,aaaa,abba,baab,bbbb etc.
(C)Due to string baaa (S->bSa->baSaa->baaa) we can eliminate this option because this is not even length palindrome.
(D)In option D we can not able to generate any string because to stop repetition S
there is no terminal symbol present.
Hence,Option(B)aSa | bSb | ∈ .