Please help with this question

For each of the following languages, prove or disprove that it is regular. (a) L_a = {uaupsilon:uupsilon L}, where L is any regular language over {a, b}. (b) L_b = {w: w {a, 6}" and w = w^R}. (c) L_c = {b^ka^nb^n:n.k Greaterthanorequalto 0}