Point S has the coordinates (6, –4).

On a coordinate plane, point R is 6 units to the left and 4 units up. Point S is 6 units to the right and 4 units down. Point T is 6 units to the left and 4 units down. Point U is 6 units to the right and 4 units up.

Which point on the graph shows the reflection of point S across the y-axis?
R
A
T
U