Answer:
a.) Instead of configuring all up before some down, all of the configurations were placed as up and down, leaving two spots empty in the 2p sublevel.
b.) There is a missing s sublevel for row 3.
c.) There are two up arrows in one of the lines.
d.) When you get to the "d" section you must subtract the number you're using by 1. So, it's supposed to be 2d to the power of 10.