<s>[INST] context: Alcohol is an enormous contributor to otherwise preventable birth defects. Sequelae include retardation of intrauterine growth, craniofacial abnormalities, and mental retardation. The occasional drink in pregnancy has not been proved to be deleterious. Isotretinoin (Accutane) is a powerful drug for acne that has enormous potential for producing congenital anomalies when ingested in early pregnancy; it should never be used in pregnancy. Tetracyclines interfere with development of bone and can lead to stained teeth in children. Progesterone have been implicated in multiple birth defects, but controlled studies have failed to demonstrate a significant association with increased risk. Patients who have inadvertently become pregnant while on birth control pills should be reassured that the incidence of birth defects is no higher for them than for the general population. Phenytoin (Dilantin) is used for epilepsy and can be associated with a spectrum of abnormalities, including digital hypoplasia and facial abnormalities. [/INST] question: In terms of birth defect potential, the safest of the following drugs is | options: A: Alcohol B: Isotretinoin (Accutane) C: Tetracyclines D: Progesterone | answer: D </s>