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Question

Doubt: Please clarify how option b is wrong.

Answer 1

I think option B is correct:

RE: (a+b)^*(a+b+Ԑ)a = (any string)(aa+ba+a) = any string end with a = {a, aa, ba, abba, baaba, ......}

Now Option B: (Ԑ+a+b^*)⁺a = (Ԑ+a+b^*) (Ԑ+a+b^*)^* a  ; we know (Ԑ+a+b^*)^* can form any string of a and b

= (Ԑ+a+b^*)(any string)a = (any string)a = any string end with a.