The figure below shows the generic sequence of spaces and direction of movement of users to and from an operation theatre after entering from a common corridor. The spaces are marked as \(P\), \(Q\), \(R\), \(S\). Choose the correct option(s). Arrows indicate flow of different users
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Trace each arrow's direction and zone: one way in before surgery = pre-operative, two way through the change area = dress change, one way out to soiled area = dirty utility, one way out to corridor after surgery = post-operative.
An operation theatre suite is always planned as a one way, zone controlled sequence: clean and sterile users move inward through a graded series of spaces (change, holding, scrub) and soiled material or a recovering patient moves outward through a separate path, so that dirty and clean traffic never cross. Use that rule to sort $P$, $Q$, $R$ and $S$.
$Q$: reached by a single straight arrow from the common corridor that crosses into the sterile zone before dropping into the theatre. This is a one way "in" path used before the operation starts, so $Q$ is the pre-operative space, where the patient is prepped and held.
$P$: sits in the semi-sterile band with a two headed arrow to both the corridor and the theatre. Staff need to go back and forth here every time they enter or leave, which only fits a change room, so $P$ is dress change.
$R$: lies outside the dashed sterile boundary and is fed by a single arrow leaving the theatre, never entering it. That one way "out, never back in" pattern is what a dirty utility room needs, for waste and soiled instruments, so $R$ is dirty utility.
$S$: also a one way arrow out of the theatre, but this one runs straight back to the common corridor, the route the patient takes once surgery is finished, so $S$ is post-operative.
Now check the four options against $P$ = dress change, $Q$ = pre-operative, $R$ = dirty utility, $S$ = post-operative. Option (A) wrongly calls $S$ "dress change". Option (C) wrongly swaps $P$, $R$ and $S$ around. Option (B) matches on $P$, $Q$ and $R$. Option (D) matches on $P$, $R$ and $S$.
Let's summarize:
One way arrows into the theatre before surgery mark pre-operative space; one way arrows out mark either dirty utility (soiled items) or post-operative (patient exit), depending on where the arrow leads.
A two way arrow always marks a room staff pass through both entering and leaving, which is the dress change room.
