The first budget customarily prepared as part of an entity's master budget is the budget. a. cash b. production c. sales d. direct materials purchases

c. sales

Explanation:

The master budget is a document that contains the aggregation of all lower-level, interrelated financial budgets and operating budgets produced by an organization and it comprises of a cash forecast, budgeted financial statements, profit and loss account and balance sheet and a financing plan.

The starting point in preparing a master budget is the preparation of the sales budget.

Hence, the first budget customarily prepared as part of an entity's master budget is the sales budget.