Why does the longer-term (15-year) bond fluctuate more when interest rates change than does the shorter-term bond (1 year)? I. Longer-term bonds have more interest rate risk than shorter-term bonds....

Why does the longer-term (15-year) bond fluctuate more when interest rates change than does the shorter-term bond (1 year)?

I. Longer-term bonds have more interest rate risk than shorter-term bonds.

II. Shorter-term bonds have more interest rate risk than longer-term bonds.

III. Longer-term bonds have more reinvestment rate risk than shorter-term bonds.