Step 1: Understand the sentence.
The sentence talks about a tyrant, meaning a cruel and oppressive ruler, who eliminates anyone he considers a rival. The blank needs a strong word indicating complete destruction or removal.
Step 2: Analyze the options.
Massacred means killing many people brutally, usually a large group, not necessarily targeted rivals.
Killed is too general and does not convey the intensity or systematic elimination implied.
Exterminated means completely destroying or wiping out, often used for eliminating enemies or rivals thoroughly. This fits the context perfectly.
Slaughtered also implies brutal killing but is more commonly used for animals or large groups, not specific rivals.
Step 3: Conclusion.
Thus, the most appropriate word is exterminated, as it reflects the tyrantâs complete elimination of rivals.