24．This is an exciting area of study，_______new applications are being discovered almost daily．

A．one by which

B．the one where

C．one in which

D．the one by which

财产转让所得，其转让财产的收入额，每次收入不超过4 000元的，减除费用800元；4 000元以上的，减除20%的费用，其余额为应纳税所得额。 ( )