What airport code represents Montreal, Canada?

The airport code representing Montreal, Canada, is YUL. This code is derived from the city's primary international airport, Montreal-Pierre Elliott Trudeau International Airport. The use of "Y" at the beginning of Canadian airport codes is a common convention, as these codes often start with the letter "Y" followed by one or two additional letters. The "UL" at the end specifically signifies this airport in Montreal, distinguishing it from airports in other cities.

In the context of the other choices, they represent different airports: MXP corresponds to Milan Malpensa Airport in Italy, MKE is Milwaukee's General Mitchell International Airport in Wisconsin, and MOB signifies Mobile Regional Airport in Alabama. Thus, YUL is the only accurate choice that relates to Montreal.