Solution:
Note that you can repeat numbers.
3 numbers between 1 to 30 including 1 and 30.
that means (30-1)+1=30 numbers.
3 slots that can be repeated, so there is the following number of combinations:

in 100 attempts, that is a 100/27000=1/270 chance or about 0.37% chance. We can conclude that the correct answer is:
