The reason cats purr is because they feel contented.
Final punctuation, I think that's all.
A. hope i can assist you!
Try answer C I think its right
Answer:
C. Christine has been at this school for the past four years.
Explanation:
The other options unnecessarily use "has" and "had" while Answer C. is the only sentence in which it is actually necessary (ex. Dontay did most of his chores last week).