The Crown has been the symbol of the state in Canada for over:

Discover Canada records this in one direct sentence about the Canadian Crown. The guide writes: The Crown has been a symbol of the state in Canada for 400 years. The duration the test wants is therefore 400 years.

Two precise commitments. Discover Canada commits the Crown to TWO specific facts: (1) it has been a symbol of the state in Canada for 400 years; and (2) Canada has been a constitutional monarchy in its own right since Confederation in 1867. So the Crown's role goes back centuries before Confederation — covering both the French and British colonial periods on Canadian soil — and continued in modern form after Confederation.

The Crown represents the entire state. Discover Canada commits the Crown's modern role to a wide range of named institutions: "The Crown is a symbol of government, including Parliament, the legislatures, the courts, police services and the Canadian Forces." So the Crown unites all the named branches and arms of Canadian government — not just the executive but also the legislatures, the judiciary, police services, and the military. The Crown's named symbolic role is therefore comprehensive.

Queen Elizabeth II carries this Canadian heritage today. Discover Canada commits the modern Sovereign to specific named facts: "Queen Elizabeth II, who has been Queen of Canada since 1952, marked her Golden Jubilee in 2002, and celebrates her Diamond Jubilee (60 years as Sovereign) in 2012." So the Queen has personally represented the Canadian Crown for many decades, marking long-service jubilees. The Sovereign reigns according to the Constitution: she is the head of state, distinct from the Prime Minister, who is the head of government. As described elsewhere in Discover Canada, the Crown is also the named tradition that includes "the focus of citizenship and allegiance" in Canada. The 400-year count covers both English and French monarchical traditions on Canadian soil — making the Canadian Crown one of the longest continuous state symbols in North America. So when the test asks how long the Crown has been a symbol of the state in Canada, the source-precise answer is 400 years.

The question is testing whether new citizens know how long the Crown has been a symbol of the Canadian state. Discover Canada commits to one period: 400 years. The right test answer matches that.

The wrong answer choices each substitute a different period. The first choice — 200 years — is half the source's named figure. The second choice — 300 years — is also below the source's named figure. The fourth choice — 500 years — exceeds the source's named figure. Only 400 years — the source's exact named period — matches.