单选题 Eva, Francis and Gigi have been in business for many years. They have always shared profits and losses equally. No goodwill account has been created in the books. On 1 January Year 7 they agree that Henry will join the partnership. Henry pays ＄25,000 as his contribution. They agree to share profits and losses equally. The Net Assets before Henry's admission is $ 60,000. After Henry's admission, the goodwill is equal to ______. (a)＄15,000. (b)＄5,000. (c)＄35,000. (d)＄20,000.