A ratio is not multiplication, so I'm just going to throw that out there first in case any other answers trip you up.
9:2 is the correct answer because there are 9 sandwiches for 2 people.
Choice (B) is true.
For (A): 5 is not a divisor of 14, whose only divisors are 1, 2, 7, and 14.
For (B): the factors of 10 are: 1, 2, 5, and 10. The factors of 15 are: 1, 3, 5, and 15. As we can see, the only, and greatest, common factor is 5.
For (C): 3 is not a factor of 13, which is a prime number.
For (D): again, 3 is not a factor of 14.
Easy!
All you have to do is make a number lower or higher according to the symbols and make it unique.
For example, on letter B, it says ____ - ____ = <1
So what you want to do is make it 0 - 0 = <1