A suffix is usually referred to as a group of letters or morpheme added at the end of a root word to form a new one. <em>Different suffixes can be used with the root word 'commit' like -ee, -ed, -ing but in these suffixes, we need to double the consonant to form a derivative due to the final syllable being stressed. Thus, the only one among the given option without having to double the consonants is suffix -ment in the formation of word "commitment" as here the final syllable is not stressed. </em>So, there is no need to double the consonants.
