Then she tells him her plan: while Duncan sleeps, she will give his chamberlains wine to make them drunk, and then she and Macbeth can slip in and murder Duncan. They will smear the blood of Duncan on the sleeping chamberlains to cast the guilt upon them.
<span>C. Is the correct answer here - bought is based on the root verb 'buy or to buy' but its sense in the sentence is set against the framework of a time from the phrase with the word 'During' and so the word of choice must become 'bought'.</span>
Change happen to happened because it is past tense