Answer: 45:18 & 35:10, B & C
Explanation:
In the question, it says a student-to-teacher ratio so that would eliminate A. Then you would divide each answer by 5 and 2 and see if it is divisible.
For Example:
45/5 and 18/2 you would get 9 and 9
35/5 and 10/2 you would get 7 and 5
10/5 and 7/2 you would get 2 and a decimal/fraction meaning it is not equivalent
So your answers would be B & C