Read the following paragraph. Which sentence is the topic sentence?


I first stopped by the store to pick up a few groceries. Then, I dropped off my letters at the post office. I had a dentist appointment in the afternoon. Finally, I attended my best friend’s birthday party in the evening. My day was long and exhausting.

A)I first stopped by the store to pick up a few groceries.

BThen, I dropped off my letters at the post office.

CI had a dentist appointment in the afternoon.

DFinally, I attended my best friend's birthday party in the evening.

E)My day was long and exhausting.