Studies on a machine that molds plastic water pipe indicate that when it is manufacturing $1-$inch diameter pipe, the process mean turns out to be $0\mathrm{.}9$ inches and the process standard deviation is $0\mathrm{.}04$ inches. The customers define a good quality plpe as one having a diameter of one$-$inch with a tolerance of plis or minus $0\mathrm{.}20$ inch. What lievel of quality does the process currently deliver?

$25$ igma

$35$ igma

$4$ Siema

$5$ Sigma

$6$ Sigma

None of the above