Consider a sequence $729,81,9,1 , \ldots \ldots \quad 3 ^ { 6 } , 3 ^ { 4 } , 3 ^ { 2 } , 3 ^ { 0 } \ldots$
Let $\mathbf { P } _ { \mathbf { n } } =$ product of first $\mathbf { n }$ terms of the given sequence and $\sum _ { n = 1 } ^ { 40 } \left( P _ { n } \right) ^ { \frac { 1 } { n } } = \frac { 3 ^ { \alpha } - 1 } { 2 \times 3 ^ { \beta } }$. Then the value of $\alpha + \beta$ is\\
(A) 75\\
(B) 73\\
(C) 76\\
(D) 81