1-Design an E/R diagram for the following situation: Doctors prescribe drugs for patients. A given doctor can prescribe many drugs for a certain patient. Sometimes a doctor may not prescribe any drug to a patient. Many doctors can treat a patient. Many doctors can prescribe the same drug to the same patient. A prescription can involve more than one patient (e.g., a mother and her baby) and more than one drug, but is associated with a unique doctor. Furthermore, if a prescription involves multiple patients, the doctor prescribes each drug on the prescription only for one patient. You can assume that any given drug appears only once on a prescription.