Suppose that a three$-$stage process had relliability ratings of $7.,8,$ and $\mathrm{.}9$ at each station and that a fallure at any station remresented a failure for the entire nrocese. If each station is given a redundanit check with $7$ relliability, please answer the following questions.

What is the original reliability of the system without redundant check?

$448$

$504$

$608$

$804$

$830$