B. Johnson joins the partnership of Byers and Carter by paying $30,000 in cash. If the net assets of the partnership are still the same amount after Johnson has been admitted as a partner, then Johnson: 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 either an intestment of assets or by purchase of a partner's interest