user
Two Russions where walking down the street the one is the dad of the otherones son how do you explain that?
A: relative
B: grey
C: parking zone
D: one is mom
E: old man
assistant
<|begin_of_thought|>

Deep Thought is thinking for 7.5 million years.

<|end_of_thought|>

<|begin_of_solution|>

D

<|end_of_solution|>