Tom is a very discerning individual who keeps track of his income and expenditures. He lives in a rented house but wants to own a house in the future. To do this, Tom prepares an elaborate financial plan and tries sticking to it very strictly. However, he is concerned about eventualities that might occur in the future and disturb his plan. Which practice can help him prepare for any problems with his plan? A. regularly review and revise his plan B. get his plan reviewed and recreated by a finance expert C. make several investments to increase his source of income D. abstain from making expenses, excluding few necessary ones