Answer: Option C.
Vehicle
Step-by-step explanation:
It is vehicle because, vehicle is a non living source that serve as an agents or carrier if infectious diseases and that infect or affect many people.
In this case a drinking glass of water is a non living source because it is does not have life and the pathogens that causes influenza are in it and as people begin to share the drinking glass of water, the pathogens are transmitted and they have influenza.