If the market interest rate (the required rate of return that investors demand) unexpectedly increases, what effect would you expect this increase to have on the prices of long-term bonds?

A) The prices of long-term bonds should first fall and then increase 

B) The effect of interest rate on price is not investigated yet 

C) The prices of long-term bonds should increase 

D) The prices of long-term bonds should fall 

E) The prices of long-term bonds will not depend on interest rate fluctuations