Is there know answer to pick from?
Answer:
Take a moment to think about the last time something startled you. Did you make a noise when it happened? Maybe you SCREAMED. Or perhaps you SQUEALED. You may have even SHRIEKED. When those noises came from your mouth, they may not have seemed like anything important. After all, a scream or a squeal or a shriek is just a sound, right? On paper, however, those sounds are something much more!
Explanation:
The answer is C) As the policeman walked up to him.
Infinitive phrase because infinitives have "to ___" and the blank is an action word ☺
