The answer to this is Aa -- Ch. A lot of offices usually file the files that they have based on the last name of the person. In this case, the name of the person is Dan Cedar. We can disregard his first name following the usual way of filing folders. Cedar will then be placed in the first option which is Aa - Ch.
If in case the office files in an unusual manner which mean that Dan will also be considered, the right answer will be Aa -- Ch. Filing can be very important because it will allow different files to be easily accessible. Just imagine if all the files are jumbled. It can make searching for the right files much harder than what you may have expected.