D.
If you are also asking this from a personal standpoint, my advice is that the dual enrollment courses are much easier. However, this may not be the best option depending on which college it is based through (Dual credit is NOT universal, and there are some colleges, especially the ones that are harder to get into, that will not accept transfer credit from many colleges.) My advice would be, if you don't know where you are going to college yet, to take the AP and study a lot for that test. Or, if you know where you are going, to take advantage of CLEP tests, which are easier and strictly pass/fail subject tests. Most colleges would have the AP/Transfer Credit/CLEP requirements on their websites if you do a little digging.