6. to drive
7. to help
8. /
9. To be
10. /
11. to travel
An infinitive is an essential form of a verb, always in the form of TO + verb. It gives us a basic, impersonal, dictionary form of the verb, which provides us with its meaning. In a sentence, it can complement certain verbs with incomplete meaning, such as modal verbs (e.g. I have to go), or express a purpose of some other verbs (e.g. I went to buy groceries).
The correct answer is C. Refrain. hope this helps :)
