What does this sign mean?

A)Lane reserved for buses but which can also be used by other vehicles in certain circumstances.Correct
B)Lane for slow vehicles.
C)Lane prohibited to vehicles that are not for transport or public service.
The sign indicates a lane reserved for buses. It indicates the prohibition for drivers of vehicles that are not for collective transport from travelling in the indicated lane. The mention also authorises taxis to use this lane.
In sections where the longitudinal white marking is constituted, on the outer side of this lane, by a discontinuous line, its general use is permitted exclusively to perform some manoeuvre, other than stopping, parking, changing direction or overtaking, always giving priority to buses and, where appropriate, to taxis.
Do not confuse with the "Bus stop" sign.
In sections where the longitudinal white marking is constituted, on the outer side of this lane, by a discontinuous line, its general use is permitted exclusively to perform some manoeuvre, other than stopping, parking, changing direction or overtaking, always giving priority to buses and, where appropriate, to taxis.
Do not confuse with the "Bus stop" sign.