On a motorway, when is it permitted to drive on the hard shoulder?

On a motorway, when is it permitted to drive on the hard shoulder?
A)When there are many vehicles in circulation.
B)Never.
C)When, due to an emergency or breakdown, the vehicle is travelling at an abnormally reduced speed.Correct
Drivers of vehicles with a maximum authorised weight not exceeding 3,500 kilograms who, due to emergency reasons, are travelling at an abnormally reduced speed and thereby seriously disrupting traffic, must drive on the right-hand hard shoulder, or on the minimum necessary part of the carriageway. If traffic is not being disrupted, they must drive in the right-hand lane. When these drivers are travelling on a motorway or dual carriageway, they must leave the road at the first exit.