Answer:
c. Teresa studied for an hour, outlined her paper, and then took a break.
Step-by-step explanation:
In English language, there are certain laid down rules for subject- verb- object agreement in a sentence.
The sentence is trying to show that the length of time that Teresa studied is one hour, she made an outline for her paper and then she went on a break.
All these are properly captured in the sentence;
Teresa studied for an hour, outlined her paper, and then took a break.