Answer:
Option C is the correct answer.
Step-by-step explanation:
Since a random number generator is used to select a single number between 1 and 28, inclusively;
For a fair decision to be made during the process, the number of persons in the set must be a divisor of 28.
Let's list the divisors of 28:
The divisors of 28 are {1, 2, 4, 7, 14, 28}
The only option that contains one of the divisors is option C which is 7.