The teaching here is, if you are first in a traffic queue (lights, pedestrian crossing, roundabout, etc.) you sit in 1st with the handbrake on or foot on the brake. If you're further back in the queue, put it in neutral with the clutch engaged and handbrake on.
In the test, you can do either when stopped without being penalised, regardless of where you're stopped. However, we're taught to sit in 1st at the head of a queue, as you will be penalised for hesitancy if you're not quick enough to take off.