What are the differences between return-trip, one-way trip and annual trip for International Plan?

Return Trip: Covers you for a specific returning journey which commence from and return to Malaysia.
One-Way Trip: Covers you for a specific one-way trip which commence from Malaysia but may or may not return to Malaysia (or the return date to Malaysia is uncertain). For one-way trip, coverage will cease upon arrival at the airport of the first destination country (excluding transit countries). Premium shall be determined based on travel duration of 1-5 days.
Annual Trip (Only available for International Plan): Covers you for multiple journeys within a one-year period.