A and C are equivalent.
If you look in the tenths place, they both have a five while every other place is a zero. Although C doesn't have a zero in the hundredths place and ends there, it actually has an infinite amount of zeros.
0000.5000000000 is also equivalent to A and C, the zeros are just place holders.
A and C are equivalent, they are both 5 tenths which is the same as 0.50 and 0.5.