Step 1: Idea.
What we see is the part of white light that the compound does not absorb. If one colour is taken out, the eye sees the colour opposite to it on the colour wheel.
Step 2: Apply it.
Red light is taken out. The opposite of red on the wheel is green, so the transmitted or reflected light looks green.
Step 3: Look at the options.
(A) Red is the colour that gets absorbed, so it cannot be the one seen. (B) Blue and (D) Yellow are neighbours of other pairs (blue goes with orange, yellow with violet), not with red.
Final Answer:
The compound looks green. The answer is (C).
\[ \boxed{\text{C}} \]