Consider a restricted alphabet set that is made of letters {AC, T, G}. How many 5-letter words you can form from {A, C,T,G} with the following restrictions (please justify your answer): The word ends with A. The word starts with A and ends with T. The word contains only C and G. The word does not contain C. The word does not contain AAA in consecutive positions. (For example, CTAAA, TAAAC, AAAAC are not valid.)