What is the designator code for Saint John, New Brunswick?

The designator code for Saint John, New Brunswick is YSJ. Designator codes are standardized three-letter codes assigned to airports and are used for identification in various aviation-related contexts like flight planning and air traffic control. Each airport within Canada is assigned a code beginning with the letter 'Y,' which denotes it as a Canadian airport.

In this case, YSJ specifically corresponds to Saint John Airport, which serves the city of Saint John. The remaining options refer to other airports in Canada: YQB is the code for Québec City, YOW is for Ottawa, and YTZ is for Toronto Island Airport. Thus, the association of YSJ with Saint John makes it the correct choice.