You can use the process of elimination to solve this multiple choice problem.
The first portion of this verbal expression is "15 divided by a number", so you can figure out that the first portion of the written expression would be (15/n). So, your answer choices are now limited to A and B.
The next portion says decreased by 2. Whenever you see the word "decrease", it means subtraction. So, you know that your answer would be answer B.
