Final answer:
G is a binomial variable because it meets all criteria of a binomial distribution, such as fixed number of trials and constant probability.
Step-by-step explanation:
The type of variable G, which represents the number of grandparents Leo interviews whose grandchildren are living with them, is a binomial variable. This is because there are a fixed number of trials (25 interviews), two possible outcomes (grandchildren living with them or not), constant probability of success (35% of the grandparents have their grandchildren living with them), and each trial is independent of the others. It is not a geometric variable because we are not looking for the number of trials until the first success.