Ans will be (D)
Because (D) is consisting of strings which are start with 'a' and end with 'a' . Minimum string for this language is 'a' and also atleast one 'a' with each 'b' so that no two b comes together. Each string also have atleast one 'a' greater than number of b it has.
So, the strings that accepted by the language {a,aa,aba, ababa..............} which is accepted by both left side (ab+a)*a and also right side a(ba+a)*.