Fill in the blank with the suitable article: My daughter is learning to play…

Correct answer: the

Explanation: We use "the" when referring to the instrument as the specific type being learned in that setting. "Learning to play the guitar" is the common, idiomatic phrasing when talking about lessons or instruction at a place such as a school.

• Why "the" fits: It treats the guitar as the instrument being studied in that context (e.g., music lessons at school), which is the usual way to express this idea.

• Why "a" or "an" is wrong: "A" or "an" would indicate one unspecified physical instrument. "An" is also ungrammatical before "guitar" because "guitar" begins with a consonant sound.

• Why no article is not preferred here: "Learning to play guitar" is used in some varieties (especially informal American English), but with the context "at her school" the version with "the" is more natural and idiomatic.

Example: "My daughter is learning to play the guitar at her school."