A portfolio that incurs a substantial loss due to a significant downturn in Canadian equities...

Systematic risk (market risk) affects the entire market or asset class, and cannot be diversified away. A downturn in Canadian equities impacts all Canadian stocks, making it a systematic risk.

Unique risk (A) is company-specific and can be diversified away.

Currency risk (B) arises from exchange rate fluctuations, not applicable here.

Default risk (C) applies to debt issuers failing to meet obligations, not equities.