The correct option is
B Sweet
Sour occupies the sides of the tongue and detects acidity like in lemon, orange, grape.
Bitter occupies the base of the tongue and detects unpleasantness like in caffeine, nicotine, bitter gourd.
Sweet occupies the tip of the tongue and detects sugars like jaggery.
Salty occupies tips and sides of the tongue and detects sodium chloride.
So, the correct option is C.