Lo. Lo (in this case) means “it”, in the masculine singular form.
Answer:
Question 10: When I want to study, I listen to music.
Question 11: His cousins can't.
Question 12: He/she needs to study Spanish every day.
Questions 13, 14, 15: I don't have the audio
Hope this helped!
Answer:
A. Su
Explanation:
Because Su literally translates to their. Tu means you/your and mi means mine/my.
If it were casas, then you just modify the pronoun to sus.