I think it's called infectious agent or something close to that.
From experience with my best friend, I´d say C.
Answer:
Targeted exercise should improve the performance of a certain task. Repetition of specific exercises will help improve the given task.
Answer:
Avoiding caffeine and liquids before bed, especially alcohol if you're already tired. Turning off any surrounding lights or sounds. Avoiding stimulating activities before bed. Keeping your bedroom at a comfortable temperature.