¿Cuál plan prefieres?

This is one of the most common learner questions.

• Cuál usually means which one
• Qué usually means what or which before a noun

With a noun directly after it, many teachers and grammar guides prefer:

• ¿Qué plan prefieres? = Which plan do you prefer?

And with a specific group, cuál is very common in structures like:

• ¿Cuál prefieres? = Which one do you prefer?
• ¿Cuál de estos planes prefieres? = Which of these plans do you prefer?

So ¿Cuál plan prefieres? is understandable, but many learners will hear ¿Qué plan prefieres? or ¿Cuál de estos planes prefieres? more often as the safest, most standard choices.

Prefieres is the tú form of preferir in the present indicative.

• infinitive: preferir = to prefer
• yo prefiero
• tú prefieres
• él/ella/usted prefiere

This verb is a stem-changing verb:

• prefer- changes to prefier- in many present-tense forms

So:

• ¿Cuál plan prefieres? literally means Which plan do you prefer?

Spanish often leaves out subject pronouns because the verb ending already shows who the subject is.

• prefieres already tells you the subject is you informal singular

So both are possible:

• ¿Cuál plan prefieres?
• ¿Cuál plan prefieres tú?

The version without tú is more neutral and very common. Adding tú often gives emphasis, contrast, or clarification.

After question words like qué or cuál, Spanish usually does not use the article the way English sometimes does.

So you ask:

• ¿Qué plan prefieres?
• ¿Cuál plan prefieres?

Not usually:

• ¿Cuál el plan prefieres? — incorrect

If you want to include an article, the structure usually changes:

• ¿Cuál es el plan que prefieres? = Which is the plan that you prefer?

But that is more wordy and less natural for this situation.

Cuál takes a written accent when it is used as an interrogative or exclamatory word.

That includes direct questions:

• ¿Cuál plan prefieres?

And indirect questions:

• No sé cuál prefieres. = I don't know which one you prefer.

The accent helps distinguish it from non-interrogative uses of similar words.

Spanish uses both:

• an opening question mark: ¿
• a closing question mark: ?

So a full question is written like this:

• ¿Cuál plan prefieres?

This is standard in all Spanish, including Latin America.

For a more formal or polite version, use the usted form:

• ¿Cuál plan prefiere?
• or more commonly, ¿Qué plan prefiere?

In parts of Latin America that use vos, you may also hear:

• ¿Qué plan preferís?

So the original sentence is specifically the informal singular version used with tú.

Yes. If everyone already knows you are talking about plans, Spanish often drops the noun.

Very natural options are:

• ¿Cuál prefieres? = Which one do you prefer?
• ¿Cuál de estos prefieres? = Which of these do you prefer?

This is often more natural than repeating plan if the context is obvious.

Usually, the question word goes near the beginning:

• ¿Cuál plan prefieres?
• ¿Qué plan prefieres?

A version like:

• ¿Prefieres cuál plan?

sounds unnatural in normal conversation.

Spanish question structure is not exactly the same as English, but with question words like qué and cuál, putting them first is the normal pattern.

They are similar, but not identical.

• ¿Qué plan prefieres? = Which plan do you prefer?
• ¿Qué plan te gusta más? = Which plan do you like more?

In many everyday situations, both work. But preferir is a more direct way to talk about choosing between options. Gustar más focuses more on liking.

So if you are comparing plans, products, or options, preferir is often the most precise choice.