To convert \( x = 0.264\overline{6} \) to a rational number, we need to eliminate the repeating decimal.
In this case, the repeating part is "6," which has one digit. Therefore, we multiply both sides of the equation by \( 10 \) to shift the decimal point one place to the right:
\[ 10x = 2.646666...\]
Thus, the correct answer is:
10