The correct answer is: C. for
A prescription is a written order from a doctor that authorizes a pharmacist to dispense medication to a patient. The prescription typically includes the name of the medication, the dosage, and the frequency of administration.
The word “for” is used in this sentence to indicate the purpose of the prescription. The doctor gave the prescription to the patient so that the patient could obtain the medication.
The other options are incorrect because they do not accurately reflect the meaning of the sentence. The word “with” is used to indicate that something is being used in conjunction with something else. The word “to” is used to indicate that something is being directed towards someone or something. The word “at” is used to indicate a location or position.