Which choice has an incorrectly spelled word and the spelling rule that would correct it?

Aflatest; adding a suffix beginning with a vowel.

b)noticable; double the consonant when adding a suffix .


c)noticable; adding a suffix that begins with a vowel .


I think the answer is "c."But I'm not certain ; thanks for the help in advance .

Dflattest; doubling the consonant when adding a suffix.