Which of the following best describes the english expression the quotient of four and the sum of a number and three? a. 4/x+3 b. x+3/4 c.4/x+3 d. x/4+3

Quotient means division, which is obvious by all the division answers. 
It says "Quotient of 4 AND ..." which means that four will be on top and everything else will be on the bottom. 

So now you have:

four over something unknown. 

Reading the rest of the question, "the sum of a number and three"
Sum means addition, again obvious by the answer choices. 
"a number" is an unknown, so we can set that to x
and this x is being added to by three, so therefore 
x+3 would be in your denominator. 

You final equation should look like this:;

OR answer choice A