Which of the following is correct? Please explain

a) corporate bonds are more liquid than treasury securities

b) when yield curve is upward sloping, 10-yr T-Notes yield higher than 3-yr T-Bonds

c) municipal bonds yields are higher than corporate bonds of similar credit ratings

d) all else equal - Convertible bonds yields are higher than non convertible bonds yield

e) all else equal - Callable bonds yields are higher than non-callable bonds yield