Fill in the blank with a suitable option:
"What ___________ you to do?"
"She (the doctor) told me to stay in bed for a few days."
The Past tense is
used to refer to a completed action in the past but with a clear reference to
the specific time of action in the past.
Here in the question, we see that the second person had visited the doctor and the first person is asking what the doctor told him/her. At the time of speaking the action had already occurred (i.e. the second person visiting the doctor & getting a medical advice), therefore the correct tense to use here is Simple Past Tense.
Here the sentence is the question form.
A sentence of Simple Past Tense in question form is formulated as: did + [subject] + [root form of the verb]
When asking a question with the verb "to be" the formula is : was / were + [subject]
Here the verb is tell (root form of the verb).
Therefore the correct formulation here is : did + she + tell
Therefore the correct complete sentence is:
"What DID SHE TELL you to do?"