Which variable below is NOT used to estimate task duration?

Question $31$ options:

$1)$

duration

$2)$

total amount of work, as in person hours$/$days$,$ that will be done on the task by a resource

$3)$

consumption of the resource as measured by the three$-$point technique

$4)$

the percent per day of an individual$$s time that the resource can devote to working on it