1. Which of the following assets can be considered as risk-free?

I. A 3-month Treasury bill issued by US Department of Treasury.

II. A 10-year Treasury bond issued by US Department of Treasury.

III. A 15-year municipal bond issued by the city of New York.

IV. A 15-year corporate bond issued by Apple Inc.

1. I only
2. I and II only
3. I, II, and III only
4. I, II, III, and IV