The triangle and its mirror across the given line must have same height in y-axis. Because of this, the answer it can not be C
They also must be same distance of the red line. For this reason, D is not right also.
The position of the point J in the A is in correct place. J' is in the correct position in relation to the red line. So is R to R' and A to A'. For this reason, A is the correct answer.
The points R' and A' are exchanged in the B option. For this reason, this is not the answer.
Answer:
A
