Well one way to do this problem is using mods... but I prefer this way:

List out the units digits of powers of 4:

4, 6, 4, 6, 4... see the pattern?

For powers of 5, the units digit is always 5

For powers of 8, we have the pattern 8, 4, 2, 6, 8, 4, 2, 6, 8...

You can use this to help find your answer