The correct answer is (-10, -4).
Step-by-step explanation:
D2 is a dilation with scale factor 2. This means that each coordinate in the point gets multiplied by 2:
(5, 2)→D2 = (5*2, 2*2) = (10, 4).
r(180, O) is a 180° rotation about the origin. This will negate each coordinate of the point; algebraically, (x, y)→(-x, -y). This means that
(10, 4)→r(180, O) = (-10, -4).
This is our final answer.