Choose the option where both grammar and vocabulary are correct:

I. “We looked for witnesses, but the neighbors had not seen Tootles in the act.”

II. “If Todd had not included his own name in the message, we would had no idea who was behind it.”

III. “I have knew Victoria for a long time, I can assure that she will help.”

IV. “The new drug will have been implemented within the pharmaceutical companies by this year.”