5-letter "words" are formed using the letters A, B, C, D, E, F, G. How many such words are possible for each of the following conditions? (a) No condition is imposed. There are possible "words". (b) No letter can be repeated in a word. There are possible "words". (c) Each word must begin with the letter A. There are (d) The letter C must be at the end. There are possible "words". possible "words". (e) The second letter must be a vowel. There are possible "words".