Answer:
B. Surgery
Step-by-step explanation:
I am not entirely sure but based on the definition of selection pressure (which talks about how external agents affect the survival of an organism) surgery is does not meet the definition.
A tiger hunting a prey affects the survival of prey. Beginning of ice age is an environmental agent that can affect survival of organism that cant tolerate cold. Antibiotics are drugs that can kill bacteria thus lower their survival. Surgery can actually increase survival if some form of disease is being treated.