Rule A: If a word ends in e and the suffix begins with a vowel, usually the e is dropped before the suffix is added.
Rule B: When a word needs a vowel to help its pronunciation, the e is retained when adding a suffix.
Rule C: When a word needs a vowel to keep its meaning, the final e is retained.
Rule D: The final e of the word is usually retained if the suffix begins with a consonant.

Form a new word, following the rules given above.

advise (-e) + -ing =
a0

Type the letter of the rule being followed, A, B, C, or D .

Rule:
a1