In the diagram below, lines m and n are parallel.

Which angles are contruent to $\angle 1$
A. $\angle 6$, $\angle 7$,and $\angle 4$
B. $\angle 5$, $\angle 2$,and $\angle 3$
C. $\angle 2$, $\angle 3$,and $\angle 8$
D. $\angle 6$, $\angle 3$,and $\angle 8$