Answer:
The correct answer would be, This is primarily due to the fact that memory is a constructive process.
Step-by-step explanation:
A constructive process of memory is a process in which the memories are retrieved with altered, revised or new information associated with that memory. When new information gets into the mind, the mind unconsciously attaches that new information with that of the already stored information. So as given in this question, you have your memories of the school graduation which are not fully accurate concerning this event. You seem to remember very positive aspects of that evening that did not actually happen. So what really happens is, you attached new information, or did some alternations with your stored information, or revised the stored information with the new information coming into your mind and you believe that the event happened just the way you think. This is called the Constructive Process.