When multiplying two binomials, you must multiply each term in the first binomial by each term in the second binomial. Then you add each of the products together to evaluate the expression. You can visualize this series of multiplication and addition with this formula: (x + y)(a + b) = xa + xb + ya + yb. This is known as the distributive property of multiplication over addition.

Which of these correctly evaluates the expression (c + d)(e +f)?

A. ce + cf + de + df
B. cd + ef + cd + ef
C. cd x ef
D. cd^2+ ce + ef