What is the coefficient of the middle term of (z + y)3x, if 3x is considered to be even and the middle term is the 4th term?

What is the coefficient of the middle term of (z + y)3x, if 3x is cons

1.	What is the coefficient of the middle term of (z + y)3x, if 3x is considered to be even and the middle term is the 4th term?
A.	<sup>7</sup>C<sub>3</sub>
B.	<sup>6</sup>C<sub>2</sub>
C.	<sup>6</sup>C<sub>3</sub>
D.	<sup>7</sup>C<sub>2</sub>
Answer» B. <sup>6</sup>C<sub>2</sub>