If you roll a fair 6-sided die you can get 1, 2, 3, 4, 5 or 6. In total there are 6 possibilities for the outcomes. The theoretical probability to roll each number of 6 possible is the same and equal to 1/6.
If you roll a fair 6-sided die 600 times, you can expect that near 1/6 of these attempts will get you 3's. Then you expect about 600·1/6=100 3’s (you can't suppose to get exactly 100 3's, because the experimental probability may differ from theoretical).
Answer: correct choice is A.
