Lance Joins the Partnership of Kubek and Musial by Paying

Lance joins the partnership of Kubek and Musial by paying $30,000 in cash. If the net assets of the partnership are still the same amount after Lance has been admitted as a partner, then Lance

A) must have been admitted by investment of assets.
B) must have been admitted by purchase of a partner's interest.
C) must have received a bonus upon being admitted.
D) could have been admitted by an investment of assets or by a purchase of a partner's interest.