The yield curve is usually upward sloping.

What does this mean?

(a) Investors earn a higher annualized rate of return from long-term T-bonds than short-term T-bills.

(b) Long-term T-bonds are better investments than short-term T-bills.

(c) Investors are expecting higher inflation in the future than they are today.

(d) Investors who are willing to take the risk of investing in long-term bonds on average earn a higher rate of return because they are taking more risk (that in the interim bond prices fall / interest rates rise).

Evaluate and discuss.