Which sentence correctly uses the present perfect tense? a)by next tuesday, i have called everyone on my list. b)last night i have left a voice mail message for my sister. c)i have made a few phone calls to try to obtain the information. d)i have planned to call but then i decided not to.

The answer to your question would be that the sentence that uses the present perfect tense correctly is the following one: I have made a few phone calls to try to obtain the information. That is, the correct option would be C.

The sentence shows a correct use of the present perfect tense because it refers to a past event related to the present. The speaker has made a few phone calls and now he/she has the information he/she needed.  That is, the past event relates to the current activity, topic, or conversation.