This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to find a lost friend
Make sure you have their name.
You'll have the best possible chance of finding a long lost friend if you have their full name, especially middle name. A more unusual name will make you search easier, because a name like jimmy john smith is going to turn up a huge number of people when you search.

Possible answers: (a). So, make sure you have their full name in your search. If you know * first, or the other way around, try to come up with something different the next time you go to their house.. (b). Find any graves that match the name. You'll want to search for graves outside a city that only play the beatles and are not known for the name however, you may see certain graves you know the name of.. (c). Remember that your friend might have changed their name. If they're a woman, it is even more likely that she might have changed her last name.. (d). Make sure your name is unique, too-names that don't come with the same suffix, or not easily distinguishable from one another are considered too common, based on your area. Too many of the variations can also change easily..
The answer is:
(c).