Which of the following is the correct expansion of the binomial (x + y)6?
A.
x6 + 6x5y + 15x4y2 + 20x³y3 + 15x²y4 + 6xy5+y6
B. x6 + 155y + 6x4y2 + 20x³y3 + 6x²y + 15xy5+y6
C. x6 + 6x55+ 15x4y4 + 20x³y3 + 15x²y² + 6xy¹+y6
D. x6 + 6x5y + 20x4y² + 15x³y3 + 20x²y4 + 6xy5+y6