The plant family that includes deadly nightshade, henbane, mandrake, and tobacco is Solanaceae.
Solanaceae is commonly called the nightshade family and contains roughly 2,700 species. Its members include the poisonous belladonna or deadly nightshade, black henbane, mandrake, and tobacco, but also major food crops such as potato, tomato, eggplant, and peppers. The family therefore cannot be treated as uniformly poisonous.
Many notable Solanaceae chemicals are alkaloids. Deadly nightshade, henbane, mandrake, and related genera contain tropane alkaloids such as atropine, scopolamine, and hyoscyamine. Tobacco produces nicotine, while peppers produce capsaicin, the compound responsible for their heat. These substances have very different pharmacological effects despite occurring in the same family.
The name nightshade comes from older Germanic and English terms associated with night. Solanaceae belongs to the order Solanales. The other options are different plant families: Fabaceae includes legumes, Ranunculaceae includes buttercups, and Apiaceae includes carrots, celery, and hemlock.