The purpose of closing entries is
to close or reduce the temporary account to zero.
to prepare a balance sheet.
to prepare a statement of owner's equity.
to prepare a trial balance.

To close or to reduce the temporary account to zero

Explanation:

The purpose of closing entries is to reduce the temporary account balance to zero. The temporary account is mainly used for a short period of time and for any specific work when that specific work is completed then these temporary account balance is reduced to zero

The other purpose of closing entries is to record t net amount and net income  of the organization

answer; i believe the correct answer is (sales promotion;

answer(d) encourage cooperation by improving the chances of mutually agreeable transactions;