Answer:
d. a credit to John's capital for $40,000.
Explanation:
In the question, it is mentioned that the bobby sells his interest in the partnership to John for $50,000 out of which the capital of Bobbi is $40,000 which reflects that the excess of $10,000 is the goodwill payment made by John to Bobbi.
All other information which is given is not relevant. Hence, ignored it
So, the John capital is credited for $40,000 capital