Answer: D. Either I or II
A rational number like 1/2 and 3/5 converts to a terminating decimal
1/2 = 0.5
3/5 = 0.6
Terminating means stopping. So the decimal digits do not go on forever. Any terminating decimal can be converted to a rational number. Eg:
0.97 = 97/100
-------------
Repeating decimals can also be converted to a fraction of two integers
Eg:
0.833333... = 5/6
0.2727272727... = 3/11
If the decimal doesn't have any repeating pattern, and it goes on forever, then the number is irrational.