Answer:
C
Step-by-step explanation:
The rule tells you that (x,y) ->  (x + 1, y - 3), so you take each vertice and add one to the x-values, and subract 3 from the y-values.
(-6, 4) ->  (-6 + 1, 4 - 3)     which simplifies to (-5, 1)
 (-3, -2) ->  (-3 + 1, -2 - 3)     which simplifies to (-2, -5)
(2, 1) ->  (2 + 1, 1 - 3)     which simplifies to (3, -2)