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.
B) Then, I dropped off my letters at the post office.
C) I had a dentist appointment in the afternoon.
D) Finally, I attended my best friend's birthday party in the evening.
E) My day was long and exhausting.