Determine the interval$($s$)$ for which each function is $($a$)$ increasing,

$($b$)$ decreasing, and $($c$)$ constant.

$($a$)$ Select the correct choice below and, if necessary, fill in the answer box to complete your choice.

A$.$ The function is increasing on the interval$($s$).$

$($Type your answer in interval notation. Use a comma to separate answers as needed.$)$

B$.$ The function is never increasing.