The answer is B, 7/10.
There are two options to this probability: the experimental probability that they like pepperoni pizza and the experimental probability that they don't.
The two probabilities are related by the fact that when you add the two together the probability becomes 1, or 100%.
Since the odds that they do like pepperoni pizza is 3/10, the odds that they don't is:
[tex] 1-\frac{3}{10}=\frac{7}{10}[/tex]
Thus, your answer is B, 7/10.
