Topic: Right Form of Verb,

Best Answer Explained in Below-:

The sentence "He appears to (try) his best." requires understanding the structure of the verb "to appear" followed by an infinitive. In this context, the correct completion involves conveying someone's ongoing efforts or past attempts that are relevant to the present.

Option C, "have tried," is indeed appropriate when we consider that it suggests he has made efforts in the past that are still relevant now—indicating a continuous aspect of striving to do his best. This aligns with the verb "appears," suggesting that his past attempts contribute to the current perception of his efforts.

Other options do not fit as well. Option A, "tried," represents a simple past action but lacks the present relevance. Option B, "tries," suggests a habitual action but does not align with the intention of conveying effort in the past. Lastly, Option D, "trying," does not properly complement "to appear," which requires the infinitive form.

Thus, "have tried" effectively captures the nuance of ongoing or completed efforts, making it the best fit for this sentence.