Answer:
C. Susie knew that a garage sale was a good place to find some nice, inexpensive furniture.
Step-by-step explanation:
The infinitive is the basic form of a verb. It's the form a verb has before being conjugated (changed to reveal the person, number, gender, tense, aspect, mood, or voice). It consists of the base verb with or without the infinitive marker to.
All of the given sentences contain the word to. We need to determine in which one it's used as the infinitive marker.
The correct answer is sentence C. To is located next to the word find. Together, they make up the infinitive form to find.
In the rest of the sentences, to is used as a preposition.