The witches hail Macbeth and seem to ignore Banquo at first because ?

the witches hail macbeth and seem to ignore banquo at first because ?  A : they are primarily interested in the choas  caused by the actions of macbeth : B : they are primarily interested in the banquo and fleance and want to ensure their safety :C: they are afraid of macbeth and what he might do to them : D: they fear that banquo is not strong enough to kill macbeth ? which is the correct ?