The answer is 6913.
The sequence is $a_n = 3^n - 1$.
$8 = 3^2 - 1$ $22 = 3^3 - 1$ $64 = 3^4 - 1$ $190 = 3^5 - 1$ $568 = 3^6 - 1$ $6913 = 3^7 - 1$
Therefore, the next number in the sequence is $6913$.
Option A, 1702, is incorrect because it is not equal to $3^n - 1$ for any value of $n$.
Option B, 7767, is incorrect because it is not equal to $3^n - 1$ for any value of $n$.
Option C, 6992, is incorrect because it is not equal to $3^n - 1$ for any value of $n$.
Option D, 6913, is correct because it is equal to $3^7 - 1$.