Automata Theory-

Please explain in detail these multiple choice answers on my practice exam. I'm confused about these regular expressions

13. which strings match the regex (((ale)*b)*c)*d (circle them) bc cd ababcaabaabaacabcd 14. Which strings match the regex (ab) e)d (circle them) aabbacd bcbcaad bcbcab acbbcbb 15. which strings match the regex (((a*b*)"c.)"d") (circle them) anbddddd cccbcaaa abdccccd