Which of the words given in the options can be formed using the letters of the following set only once?{a,w,r,t,I,s,o,n,m,l,b,h,e,p}APeakBMouseCHelpDCoup

The word that can be formed using the letters of the given set only once is "Help".

Step by step process:

1. Check each option one by one.
2. For option A "Peak", we don't have 'k' in our set. So, this option is not possible.
3. For option B "Mouse", we don't have 'u' in our set. So, this option is not possible.
4. For option C "Help", all letters 'h', 'e', 'l', 'p' are present in our set and each letter is used only once. So, this option is possible.
5. For option D "Coup", we don't have 'c' and 'u' in our set. So, this option is not possible.

Therefore, the word that can be formed using the letters of the given set only once is "Help".