Explanation: A conclusion is the last part of something, its end or result. In a written work, the conclusion is used to introduce some final comments at the end of the piece of writing. An argument or claim is a statement assertion that something is true. From the given options, the one that represents the purpose of an effective conclusion is the corresponding to option A: To reinforce the primary claim.
<em>Past tense indicates that the action was completed in the past. On the other hand, present perfect tense indicates that the action has been completed in the present.
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<em>Present perfect is for a period of time that continues from the past until now.
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<em>Using a time tag when using present perfect is wrong.</em>
