Answer:
C. The number 5/11 is a rational number because it is a repeating decimal.
Explanation:
The importance of this question is to distinguish a rational number from an irrational number.
A rational number can be written as a ratio or a set of repeating decimals.
An irrational number cannot be written as a ratio and cannot be represented by repeating decimals.
So out of the four options you have, the first two, A and B, are false, C is true, and D is false since rationality doesn't have anything to do with signs.
Cheers.