When is a road considered insufficiently lit?

A)When I cannot read a number plate at 10 metres.Correct
B)When a dark vehicle cannot be distinguished at 100 metres.
C)When you cannot read a number plate at 50 metres.
An insufficiently lit road is understood as one in which, with normal vision, at some point on its roadway, a number plate cannot be read at 10 metres or a dark-painted vehicle cannot be distinguished at 50 metres' distance.