Answer: Option 'D' is correct.
Step-by-step explanation:
Independent events are those events in which first event is not dependent on the other event.
A. Knowing that you have to get up early tomorrow, and going to bed before 9.
⇒ It is dependent events, as he has to get up early the next day due to which he has to go to bed early i.e. before 9.
B. Knowing that you have a test in school tomorrow, and studying the night before.
It is dependent events, as he has a test in school for which he has to study at the night.
C. Knowing that it is going to rain tomorrow, and bringing an umbrella to school.
It is dependent events, if he knows that there will be rainfall the next day, he has to bring an umbrella.
D. Knowing that you have a test in school tomorrow, and bringing an umbrella to school.
It is independent events, as there is no link between test in school and to bring umbrella to school.
Hence, Option 'D' is correct.