A fair die is tossed eight times. The probability that a third six is observed on the eight throw, is :

Question

( A ) $\frac{^7C_2 \times 5^3}{6^7}$
( B ) none of these
( C ) $\frac{^7C_2 \times 5^3}{6^8}$
( D ) $\frac{^7C_2 \times 5^3}{6^6}$