a. 3                  

b. 4        

c. 1              

d. 2

Transcript:

1. A: When do you have music?

B: I have it on Mondays.

2. A: What subjects do you have today?

B: I have Vietnamese.

3. A: When do you have history and geography?

B: I have it on Thursdays.

4. A: What subjects do you have today?

B: I have science.