The correct answer is C. reserve fund.
A reserve fund is a fund that is set aside to meet unexpected expenses or to provide a cushion against losses. In the context of a partnership, a reserve fund can be used to pay to the retiring partner or to the representatives of a partner who has died.
A sinking fund is a fund that is set aside to pay off a debt or to finance a future project. A joint life policy is a life insurance policy that covers two people, usually spouses.
Option D is incorrect because a reserve fund is the correct answer.