Which is the correct one?

i think the answer is B :)

answer: group ii. when the root is a full word except for a final e, the forms usually are spelled with -able.

explanation: the word will be deplorable. -able will be used with the word 'deplore-'. the group ii is when the root is a full word except for a final e, the forms usually are spelled with -able is used for the word deplore- because the word deplore- has 'e' at the end of it.