The correctly spelled Word is meeting. All of the other words need a double consonant. So we need :shipping trimming and hitting. You know that a word needs a double consonant in the gerund form if it has a short vowel.
When a word ia a monosyllable ending with a consonant and preceded by one vowel, the last consonant has to be doubled before adding a suffix that begins with a vowel Ex, ship + p + ing = shipping hit + t + ing = hitting trim+ m + ing = trimming When the last consonant is preceded by 2 vowels ,then it doesn't double .Just add 'ing' meet + ing = meeting wait +ing = waiting