2000 AMC 10 Problem 21

If all alligators are ferocious creatures and some creepy crawlers are alligators, which statement(s) must be true?

\textrm{I. All alligators are creepy crawlers.} \textrm{II. Some ferocious creatures are creepy crawlers.} \textrm{III. Some alligators are not creepy crawlers.}

\textbf{(A)}\ \text{I only} \qquad\textbf{(B)}\ \text{II only} \qquad\textbf{(C)}\ \text{III only} \qquad\textbf{(D)}\ \text{II and III only} \qquad\textbf{(E)}\ \text{None must be true}

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.