One mole of an ideal monoatomic gas, initially at temperature $$T$$, is heated in such a way that its molar heat capacity during the process of heating is $$C = 2R$$. The volume of the gas gets tripled at constant pressure during the process. The final temperature attained by the gas is

A

$$3T$$

B

$$3^2T$$

C

$$\frac13T$$

D

$$3^3T$$