The correct answer is C. Opium Poppy.
Morphine is a naturally occurring opiate alkaloid found in the opium poppy, Papaver somniferum. It is the most abundant and therapeutically useful of the many opiate alkaloids, and is one of the most widely used opioids worldwide. It is a white, crystalline powder that is soluble in water and alcohol. Morphine is used to treat moderate to severe pain, and is also used to treat cough and diarrhea. It is available in oral, injectable, and transdermal forms.
The other options are incorrect. Cocoa is a plant that is used to make chocolate. Belladonna is a plant that is used to make atropine, a drug that is used to treat eye problems. Tannin is a substance that is found in many plants, and is used to make leather and ink.