Give regular expressions for these languages:

(a) {w{a,b}* | w contains at least three bs}

(b) {w{a,b}* | every third symbol of w is b}

(c) {w{a,b}* | w contains at most two as}

(d) {aⁿ | n is a multiple of 2 or a multiple of 3}

(e) {w{a,b}*| w does not contain exactly two as}