An invEstor purChAsEs 200 shArEs oF mErxx on mArgin. thE shArEs ArE trADing At $40. initiAl AnD mAintEnAnCE mArgins ArE 50 pErCEnt AnD 25 pErCEnt. iF thE invEstor sElls thE stoCk whEn thE priCE risEs to $50 At yEAr-EnD, thE rEturn on thE invEstmEnt woulD BE ClosEst to:
A、

A、50.00%.

B．

B、18.75%.

C．

C、25.00%.