You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: SHAKESPEARE 
Clue: "Twelfth Night" opens with, "If music be the food of love," do this
play on

Category: PART: CHARLES 
Clue: In the '80s, he played Charles Ryder, a central character in TV's "Brideshead Revisited"
jeremy irons

Category: MEDICAL ISSUES 
Clue: Parasitic protozoa called plasmodia cause this disease; female Anopheles mosquitoes transmit the parasite to humans

malaria