What is the degree of the polynomial in the expression below?

x6 + 3 - 2x2 + 4x7 - 4x

A. 7

B. 6

C. 4

D. 5

For a term with one variable, the degree is the variable's exponent. With more than one variable, the degree is the sum of the exponents of the term with the highest value of exponent. For this expression the degree would be 6. Therefore, the correct answer is option B.