What is the minimum speed at which one must travel on a motorway without justified cause?

What is the minimum speed at which one must travel on a motorway without justified cause?
A)45 km/h.
B)50 km/h.
C)60 km/h.Correct
The maximum speed at which we will travel on a motorway is 120 km/h and the minimum speed for all vehicles will be 60 km/h. We are prohibited from travelling below that speed without justified cause.
Any driver who, for emergency reasons, is forced to drive their vehicle on a motorway or dual carriageway at an abnormally reduced speed must leave it at the first exit.
If travelling at an abnormally reduced speed seriously disturbs traffic, you must travel on the right verge if it is sufficient, with the hazard lights on. (The vehicle's MAM must not exceed 3,500 kg).