Both are correct, the only difference is that "has sent" is in present tense and "had sent" is in past tense. e.g. Mike has sent me a letter. (present tense)Mike had sent me a letter. (past tense)
Have sent - is a present perfect tense and active voice that describe a certain experience in the past up to now... Had sent-is a past perfect and also an active voice that describe a certain...
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