A two-way frequency table is used to approximate conditional probabilities by writing the ratio of the intersection of the two conditions with the given condition in the denominator and the preference in the numerator. This means that to find the conditional probability of one event occurring given the occurrence of another event, you take the count of the outcomes where both conditions are satisfied (the intersection) and divide it by the total count of outcomes that satisfy the given condition.
In summary, the correct response is: by writing the ratio of the intersection of the two conditions with the given condition in the denominator and the preference in the numerator.