Answer: a. Stop being so indecisive and take immediate action.
In this passage, Macbeth complains about not acting decisively sooner. He states that, from now on, he will make sure that his hands immediately obey what his heart feels. He resolves to take immediate action to achieve his goals. He also decides to storm Macduff's castle and kill his wife, children, and all of his relatives. He has also resolved to do so before his motivation decreases.