Answer:John's decision to buy the lottery tickets under these circumstances would best be explained by the availability heuristic.
Explanation:
Availability heuristic means the where people make judgement based on the immediate happenings. In this case John has a mental though of judgement that his friend has won the lottery jackpot he could also win the lottery he has made purchases though his income is low.
Based on the event that Rosika has won the lottery John has made the decision to buy the lottery. So he has evaluated lottery that he can also win some amount and purchased the tickets.