Which is the correct formula for the average inventory in the EPQ model?

Multiple choice question.

$($Q$/2)$H $+($D$/$Q$)$S

$($Imax$/2)$H

Imax$/2$

$($Imax$/2)$H $+($D$/$Q$)$S

$($Qp$/$p$)($p$-$u$)$

$2$DSH

$$pp$$u