Answer:
Option A, insulin
Explanation:
At current, oral insulin for human use is not a reality due to its degradation in the gastrointestinal (GI) tract, though it is believed that oral administration would yield better medication compliance than subcutaneous routes that are available and on the market at the moment.
Insulin is, instead, drawn up from a vial into the barrel of a needle and injected into the fatty tissues under the surface of the skin. Glipizide (brand name Glucotrol), acarbose (brand name Precose), and rosiglitazone (brand name Avandia) are all antidiabetic medications that are taken by mouth, or orally.
Therefore all of those options except for insulin, option A, are oral hypoglycemic medications.
