A. No
A. No
B. Yes
C. Yes, but only if you can make the pass without crossing the yellow line and can see 100m ahead of you for the whole time you are passing
The yellow line is a road marking that you must not cross unless directed to do so by police, or you are turning into a driveway.
The yellow line is called a no-passing line and it's usually there because it's unsafe to cross the centre line. There might be a hidden dip or crest, or a corner that you can't see through. Or, it might have been an accident blackspot in the past and it is safer to not overtake there.
Passing lanes are also marked on three-lane roads so that traffic travelling in the direction with two lanes is not permitted to use the third lane.
No-passing lines are warned in advanced with a broken yellow line which you can see starts a A. The line begins at C. You must not start to pass on a broken or dashed yellow line, but you can move back into your lane if you are already overtaking.
The only time you can overtake when there is a yellow no-passing line is if the lane is wide enough for two vehicles, you can see 100m of clear road in front of you for the whole time you are passing, and you stay on your side of the yellow line.