Answer: Choice A
Explanation: The most important entry for a journal is the date, so that you know when the entry was added and what time during your life the entry relates to. While the entry number would help keep the entries organized and in order, it is not entirely necessary if you also have the entry date. Choice D also doesn't make any sense, because who is this instructor and why is that even a choice? So choice A, the entry date is what should appear at the top of every journal entry.
Technically the answer could be both A and C, as both are a good idea to add to each journal, but if you could only choose one answer, it would have to be choice A, the entry date, because it already goes through chronological order. Hope this helps!