The correct option is
C Rauwolfia serpentinaRauwolfia serpentina is
Indian snakeroot or sarpagandha. It is a species of flowering plant in the family
Apocynaceae.
Rauvolfia serpentina contains a number of bioactive chemicals, including yohimbine, reserpine, ajmaline, deserpidine, rescinnamine, serpentinine. Reserpine was used in an attempt to treat high blood pressure and mental disorders including schizophrenia. So, it is a medicinal plant.
Brassica oleracea is the species of plant that includes many common foods as cultivars, including cabbage, broccoli, cauliflower, kale, Brussels sprouts, collard greens etc.
Coffea arabica (coffee) is not a medicinal plant.
Cryptostegia grandiflora or rubber vine smothers and kills native vegetation. It is not a medicinal plant.
Thus, the correct answer is option C.