Astronomy college course/Wikipedia Sidereus Nuncius/Quiz01/5

This question should be reworded so that the answer has the actual two answers of c and d. It should be like 1. correlate dark and light regions with terrain 2. measure the height of mountains 3. both 1 and 2 4. to classify stars 5. to terminate his enemies The answer is 3.

This question is very confusing and doesn't seem to make sense. I feel there is a better way to word this.

What two are the answers? We don't know.