Which statements about zip merging are correct? (multiple answers possible)

At about 50 metres before the narrowing you merge into the resulting space without braking

You only need to adjust your speed right at the narrowing itself; for the 300 metres before it you just keep driving as you were

At about 300 metres before the narrowing you already adjust your speed to the adjacent traffic

Every driver on the through lane lets exactly one driver from the obstructed lane go first each time

Explanation

False — trap: the early adjustment phase skipped. Already at 300 metres before the narrowing you adjust your speed (Book p.155).