Hey can you me posted picture of question

A monomial is polynomial containing one term. Consider the options:

Option A: y/x 
The polynomial cannot involve division by a variable. So this is not a  polynomial and therefore not a monomial.

Option B: Contains only 1 term. So it is a polynomial

Option C: Contains more than 1 term. So not a monomial

Option D: Contains a negative exponent. So not a polynomial and therefore not monomial.

So the correct answer is option B