D is correct
A is wrong because is should be are
B is wrong because does should be do
C is wrong because has should be have
A.) I was thrilled to find my keys they had been lost since yesterday.
This is a "fused sentence" or also known as a run-on sentence.
Doctors examine medical history of the patient, order, perform & interpret diagnostic tests before prescribing the medicine. Mathematics required for a doctor are college algebra, trigonometry, calculus, linear algebra, statistics & probility. They use statistical models to guide diagnoses & treat. Becoming a doctor means learning everything there is to know about the human body. The human body itself is an incredible thing to study and medical students and doctors have the opportunity to further examine it with the most innovative technology.
