The novels written by the author sell best, but five years ago no one could have imagined how great a role he _____in the literary world.

A．was playing

B．was to play

C．had played

D．played

小明在研究某个电路的总电功率P随其中的一个电阻R的阻值变化关系时，测量并记录了如下表所示的实验数据，请根据表格中的数据归纳出总电功率P和电阻R的关系：P=        。