ANSWER
B. a reflection across the x-axis
Step-by-step explanation
The given triangle has vertices
A(-2,3)
B(3,4)
C(1,-2)
The image triangle has vertices
P(-2,-3)
Q(3,-4)
R(1,2)
We can see that the mapping for the above transformation is

This is the mapping for reflection across the x-axis.
The correct choice is B.