Choose the correctly formed question.

Answers:

The correct answer is "What color car do you want to buy?"

The pattern is: What + attribute + noun + auxiliary + subject + verb? The narrowing phrase "what color car" comes first, then normal question word order follows (do you want).

"What color you want to buy car?" is wrong because it uses statement word order (no auxiliary "do") and puts "car" at the end instead of inside the narrowing phrase. "What do color car you want to buy?" incorrectly splits the auxiliary from the subject. "You want to buy what color car?" is statement order, not question order.