Just question number 4, thank you

For a word x, we use x^r to denote its reverse (e.g., the reverse of abaac is caaba). For a language L, we use L^r to denote {x^r: x elementof L}. Show that if L is regular then so is L^r. Assume that L is ((aa + bbb)*c)*bc. What is a regular expression for language L^r