William, a project manager, needs to prepare the budget for a new software development project. To do so, he takes inputs from other managers who have worked orn similar projects in the past. After estimating the overall project cost, he gives the estimates to his team members so that they car split up the cost of each individual task involved in producing the required deliverable. In this scenario, William is using:.

a. top-down budgeting

b. bittom-up budgeting

c. agile project budgeting

d. dynamic matrix budgeting