What is the probability of being served immediately in a two$-$server model?

Group of answer choices

$0\mathrm{.}503$

$0\mathrm{.}497$

$0\mathrm{.}836$

$0\mathrm{.}331$

$0\mathrm{.}110$

$0\mathrm{.}669$

$0\mathrm{.}946$