The correct answer is A. debited to that process a/c.
Expenses relating to a particular process are debited to that process account. This is because expenses are incurred in order to generate revenue, and the revenue generated by a particular process is recorded in that process’s account. By debiting expenses to the process account, we are able to track the costs associated with each process and to see how profitable each process is.
Option B is incorrect because expenses are not credited to accounts. Credits are used to record increases in assets or decreases in liabilities. Expenses are decreases in assets, so they are debited.
Option C is incorrect because costing profit and loss accounts are used to record the costs of goods sold and the expenses incurred in generating revenue. Expenses relating to a particular process are not costs of goods sold or expenses incurred in generating revenue, so they are not recorded in costing profit and loss accounts.
Option D is incorrect because profit and loss accounts are used to record the revenues and expenses of an entire business. Expenses relating to a particular process are not revenues or expenses of an entire business, so they are not recorded in profit and loss accounts.