I think this is a very subjective question. You have to choose an answer from the options after reading a passage.
Here is the relevant part of the passage:
All sunlike stars are born binaries. Most split up, while the rest become tight binaries.
And here is the question
How many sunlike stars tighten together?
- A) Some
- B) Most
- C) Almost all
- D) Very small number
I thought the answer would be "D", "very small number". The reason is as most of the stars are split up what is remaining should be very small number. According to the tutor it's B, "some". I am sure B is not really wrong, but which is more accurate here?