Answer:
max (max (max (population1, population2) , population3), population4)
Explanation:
max accepts two int arguments and returns the value of the larger one:
max (i,j) = i if i>j or =j if j<i
Four int variables, population1, population2, population3, and population4
max (population1, population2) ⇒ return the larger one between population1 and population2
max (max (population1, population2) , population3) ⇒ return the larger one between the largest one between population1 and population2 and population3
max (max (max (population1, population2) , population3), population4) ⇒ return the larger one between population1, population2, population3 and population4
An expression whose value is the largest of population1, population2, population3, and population4 by calling max is:
max (max (max (population1, population2) , population3), population4)