Answer:
C. 19.23%
Explanation:
We simply have to sum up all the times he had a six then divide that by all the times he rolled the die.
Total times he got 6: 5 + 3 + 11 + 11 = 30
Total times he rolled the die: 39 + 21 + 55 + 41 = 156
The experimental probability is then 30 / 156 = 19.23%
It's a bit higher than expected (1/6 or 16.66%), but the sampling is relatively small. If he were to throw it a thousand times, he'd probably be much close to the theoretical probability.