We use the following reflection rule:
(x, y) = (x + 1, y)
We have then:
M (-3, 1) ---> M '(- 2, 1)
O (1, 4) ---> O '(2, 4)
P (3, -1) ----> P '(4, -1)
Answer:
The new vertices are
M '(- 2, 1)
O '(2, 4)
P '(4, -1)
Graph five (last from left to right) is the correct one.