What does macbeth tell the murderers is the reason that he cannot kill banquo himself? what do you think is the real reason macbeth hires murderers to kill banquo

Macbeth shares similar friends to Banquo and he realizes that he may lose his friends if he himself does murder him. Macbeth murders him because the witches told Macbeth that Banquo's offspring would be King which sort of implies that they would replace Macbeth. Also, it seems that Banquo was becoming suspicious of Macbeth of having Duncan murdered. 

Counterclaim text which gives it a defensive manner

Inform should be the answer