Hi, my answer for section d of the problem was incorrect, I couldn't figure out a different answer plz help

3.49109E+10 90 + 910 + 911 0 0 (1 point) We want to build 13 letter "words" using only the first n = 9 letters of the alphabet. For example, if n = 5 we can use the first 5 letters, {a, b, c, d, e} (Recall, words are just strings of letters, not necessarily actual English words.) a. How many of these words are there total? 9 ** 13 b. How many of these words contain no repeated letters? 0 c. How many of these words start with the sub-word "ade"? 9 ** 10 d. How many of these words either start with "ade" or end with "be" or both? 9**8 + 9**10 e. How many of the words containing no repeats also do not contain the sub-word "bed"