The correct option is D Had got
Let’s examine the sentence: “If he got his enemy in his hand, he would have crushed him to death.” The sentence uses the third conditional. The third conditional is used to talk about 'impossible' conditions. They are impossible because they happened in the past and we cannot change them.
It is formed in the following way: If + past perfect, would have + past participle
So, the verbs in the ‘if’ clause should be those of past perfect. The sentence needs the helping verb ‘had’ before the action verb ‘got.’ This would change the tense of the ‘if’ clause to past perfect as required. Hence, Option C is the correct answer.