The Grey Cup is awarded for the championship of:

Discover Canada records this in one direct sentence. The guide writes: Canadian football is a popular game that differs in a number of ways from American football. Professional teams in the Canadian Football League (CFL) compete for the championship Grey Cup, donated by Lord Grey, the Governor General, in 1909. The league the test wants is therefore the Canadian Football League (CFL).

Three commitments in one sentence. Discover Canada commits the Grey Cup to THREE specific facts: (1) championship of the Canadian Football League (CFL); (2) donated by Lord Grey; and (3) donated in 1909. So the cup is the football-equivalent of the Stanley Cup — a Crown-donated championship trophy.

The Grey Cup parallels the Stanley Cup. Discover Canada commits TWO Crown-donated championship trophies in Canada: Stanley Cup (donated by Lord Stanley, the Governor General, in 1892, for the National Hockey League championship) AND Grey Cup (donated by Lord Grey, the Governor General, in 1909, for the Canadian Football League championship). So both major Canadian sports — hockey and football — have Crown-donated championship trophies, named for sitting Governors General who gave them. The pattern reflects the role of the Crown in Canadian sport.

Canadian football is distinct from American football. Discover Canada commits Canadian football to a separate identity: "a popular game that differs in a number of ways from American football." So Canadian football is its own game with distinctive rules — the most famous differences include three downs (instead of four), a longer field, and twelve players per side (instead of eleven). The CFL's professional teams compete annually for the Grey Cup. The guide also identifies "hockey" as Canada's most popular spectator sport and "the national winter sport", with "Canadian football" as "the second most popular sport." So when the test asks the league of the Grey Cup, the source-precise answer is the Canadian Football League (CFL).

The question is testing whether new citizens know which league awards the Grey Cup. Discover Canada commits to one league: the Canadian Football League (CFL). The right test answer matches that.

The wrong answer choices each substitute a different sport's league. "The National Hockey League" awards the Stanley Cup — not the Grey Cup. The third option is not named in the source. The fourth option is also not named. Only the Canadian Football League — the source's exact named league — matches.