Q65. The sum of all rational terms in the expansion of $\left( 2 ^ { \frac { 1 } { 5 } } + 5 ^ { \frac { 1 } { 3 } } \right) ^ { 15 }$ is equal to :\\ (1) 3133\\ (2) 931\\ (3) 6131\\ (4) 633