Carmen simplifies the expression and gets the coefficient of y is 10. Thus, the correct option is C.
<h3>What is simplification?</h3>Simplification is to make something easier to do or understand and to make something less complicated.
Given
Carmen simplifies the expression .
We can add x term with x, y term with y, and constant with constant.
On simplifying, we have
Thus, the coefficeint of y is 10.
More about the simplification link is given below.