Answer:
the (speaker) inquired for how long (the doer) has been learning the guitar.
Explanation:
from direct speech to indirect speech some things change.
in the sentence above the tense, format of the sentence and the pronoun changes.
the question will be formatted into a statement rather than a question. the tense will change into past tense. the pronouns you will change depending on whom the question was asked to.
in this sample the genders nor the persons have not been identified hence just at liberty to do as you please.
