What does this sign indicate?

A)That a minimum distance of 70 metres must be kept from the vehicle travelling ahead.
B)That overtaking is prohibited.
C)It serves as a general reminder that the mandatory safety distance between vehicles must be maintained.Correct
This is the minimum separation sign. It prohibits driving without maintaining the safety distance from the vehicle ahead. This distance is the one that allows us to stop, in the event of sudden braking, without colliding with it, taking into account speed and the conditions of grip and braking. Furthermore, if we are driving without signalling our intention to overtake, this separation must allow the vehicle behind to overtake safely.
For these purposes, drivers of vehicles with a GVW of more than 3,500 kg and vehicles and vehicle combinations more than 10 metres in length must maintain a minimum separation of 50 metres.
In tunnels and underpasses, the general safety distance shall be at least 100 metres or an interval of 4 seconds, and for vehicles with a GVW of more than 3,500 kg, 150 metres or 6 seconds. If the sign shows an indication in metres, remember the prohibition on driving without maintaining a separation from the vehicle ahead equal to or greater than that indicated on the sign, except when overtaking. (Photo 1)
For these purposes, drivers of vehicles with a GVW of more than 3,500 kg and vehicles and vehicle combinations more than 10 metres in length must maintain a minimum separation of 50 metres.
In tunnels and underpasses, the general safety distance shall be at least 100 metres or an interval of 4 seconds, and for vehicles with a GVW of more than 3,500 kg, 150 metres or 6 seconds. If the sign shows an indication in metres, remember the prohibition on driving without maintaining a separation from the vehicle ahead equal to or greater than that indicated on the sign, except when overtaking. (Photo 1)