Which of the following is false about zero-based budgeting (ZBB)?

a. It requires managers to prepare budgets each period from a zero base.

b. An organization may find it practially impossible to review and examine all of its activities from the zero-budget level every year

c. It allows all activities or function to be included in the budget unless managers acnnot justify their needs

d. It requires budgeting teams to perform in-depth reviews of all budget items