The Correct answer is C) x² - 4 .
A binomial is an expression that contains the sum of two distinct terms. In this case, the terms are x² and -4.
A) Contains 3 terms: x², -4x, and 2. Notice that, since x and x² have different exponents, they are considered distinct terms (you can't simplify the expression any further, unless you know what the value for x is)
B) Contains only one term, x²
D) Contains 4 distinct terms, 2x², 3x, -1, and y