Answer:
The correct answer is the option D: At any time in the planning period.
Explanation:
To begin with, in the field of accounting and bussines management the concept known as "flexible budget" refers specifically to the type of budget that a company uses whose primary characteristic is that it is adjustable to the situation and therefore that it goes changing all the time according with the changes that happen in the levels of volumen and or activities, including expenses and revenues as well. So that is why that a flexible budget may be prepared at any time in the planning period for the company because it adjusts to the context.
