After the switch shown in figure A is closed, there is current i through resistance R. Figure B indicates current variation curves a, b, c and d for four sets of values of R and capacitance C :

A) $R_0$  and  $C_0$             B) $2R_0$  and  $C_0$               C) $R_0$  and  $2C_0$            D) $2R_0$  and  $2C_0$

Which set goes with which curve?