a.10 b.102 ,c.204 or d.255
5.100 x 2%/100% <-- this is how we convert the percentage to a decimal so that we can work with it
5.1 x 0.02 <-- notice I dropped those 00's after the tenths place, we don't need them, test makers use tricks like that to make a problem seem more difficult than it really is
0.102 <-- which is answer option b.
Hope this helps!