When a trinomial is factored as (x+m)(x+n), what is the sum of m and n?

a. the degree of the trinomial

b. the constant term of the trinomial

c. the coefficient of the x-term of the trinomial

d. the coefficient of the x^2-term of the trinomial

Hello : 
(x+m)(x+n) =x² +mx +nx +mn
a trinomial is factored as (x+m)(x+n) is : x² +(m+n)x +mn

A. The degree of the trinomial : 2

B. The constant term of the trinomial : mb

C. The coefficient of the x-term of the trinomial : m+n

D. The coefficient of the x^2-term of the trinomial : 1

What are the options for plato