Vary in total directly and proportionately with changes in activity level.

$2)$ Remain the same in total regardless of changes in activity level.

$3)$ Remain the same per unit at every activity level.

$4)$ Vary per unit inversely with activity.

$5)$ Change in total but not proportionately with changes in activity level.

$6)$ Constant only within certain ranges of activity.

Which of the items above best describes mixed costs?

$1)$ Vary in total directly and proportionately with changes in activity level.

$2)$ Remain the same in total regardless of changes in activity level.

$3)$ Remain the same per unit at every activity level.

$4)$ Vary per unit inversely with activity.

$5)$ Change in total but not proportionately with changes in activity level.

$6)$ Constant only within certain ranges of activity.

Which of the items above best describes mixed costs?

$2$ & $4$

$1$ & $4$

$4$ & $5$

$3$ & $5$