Must a driver joining a road using an acceleration lane first make sure they can do so without danger?

A)No, because they have right of way.
B)No, because other drivers must facilitate their merging.
C)Yes, and they must not begin the manoeuvre until they are sure it is safe.Correct
On roads equipped with an acceleration lane, a driver intending to use it to join the carriageway must make sure at the beginning of that lane that they can do so without danger to other users travelling on that carriageway, taking into account their position, trajectory and speed, and even stopping if necessary. They must then accelerate to reach the appropriate speed at the end of the acceleration lane in order to merge into the flow of traffic on the carriageway.
Although other drivers must facilitate the merge as much as possible, they have priority over us.