Answer:
D
Step-by-step explanation:
The reflection across the y-axis has the rule:
(x,y)→(-x,y).
So, the vertices of the triangle ABC after reflection across the y-axis will have coordinates:
- A(1,3)→A'(-1,3);
- B(3,6)→B'(-3,6);
- C(5,3)→C'(-5,3).
Hence, correct option is D
