Formal:
* 你最喜欢的颜色是什么？ (Nǐ zuì xǐhuān de yánsè shì shénme?) - This is the most direct translation and is suitable for formal settings.
Informal:
* 你最喜欢什么颜色？ (Nǐ zuì xǐhuān shénme yánsè?) - This is a more casual way to ask the question.
* 你最爱什么颜色？ (Nǐ zuì ài shénme yánsè?) - This is a very informal way to ask, using the word "爱" (ài) which means "love" and is usually used for strong emotions.
Example in conversation:
A: 你最喜欢的颜色是什么？ (Nǐ zuì xǐhuān de yánsè shì shénme?)
B: 我最喜欢蓝色。 (Wǒ zuì xǐhuān lán sè.)
A: 哦，我也喜欢蓝色。 (Ó, wǒ yě xǐhuān lán sè.)
Translation:
A: What is your favorite color?
B: My favorite color is blue.
A: Oh, I like blue too.