When a restaurant stays open for lunch service even though few customers patronize the restaurant for lunch, which of the following principles is $($are$)$ best demonstrated?

$($i$)$ Fixed costs are sunk in the short run.

$($ii$)$ In the short run, only fixed costs are important to the decision to stay open for lunch.

$($iii$)$

If revenue exceeds variable cost, the restaurant owner is making a smart decision to remain open for lunch.

$($i$)$ and $($ii$)$ only

$($ii$)$ and $($iii$)$ only

$($i$)$ and $($iii$)$ only

$($i$),($ii$),$ and $($iii$)$