Explanation:

General risk factors are broad market factors that affect multiple securities, while specific risk factors are unique to individual securities:

• I. Exchange rate: ✓ General risk factor - affects all securities denominated in foreign currencies
• II. Mortgage-backed securities: ✗ Specific risk factor - applies only to mortgage-backed securities
• III. Zero-coupon bond: ✗ Specific risk factor - applies only to zero-coupon bonds
• IV. Interest rate: ✓ General risk factor - affects all fixed income securities

Therefore, only exchange rate and interest rate are general risk factors.