C.
Sometimes children will regress a little bit then bounce back. It is very common. My son who is 6 sometimes has accidents every so often. The important thing is not to make a big deal out of it to where they feel inadequate. Doctors have said that boys take a little longer than girls. Unless it continues to where you think there is a medical problem, please do not worry about it. One thing I have found works is to stop fluids 1hr or 2 (depending on what works for you) before bed and have them go to the bathroom right before bed and sometimes if you wake up in the middle of the night, have them go (or carry) to the bathroom if you able to. All the best.