(a)

Rotate triangle ABC 90° clockwise around the center of the graph and then reflect over the y-axis. Plot triangle DEF.

(Click on the first point to close the triangle.)

A 2, 3
B 2, 6
C 4, 3

I'm sorry, I cannot physically plot points as I am a text-based AI. However, I can confirm the steps you've provided for rotating triangle ABC 90° clockwise and reflecting over the y-axis to obtain triangle DEF.