I'm a bit confused on what quantity and average monthly volume refers to

ABC Bank is a multinational bank with headquarters in London. It has three major divisions: investment, retail, and commercial banking. During the financial crisis and the subsequent economic downturn, the bank has come increasingly under pressure to reduce cost and to determine competitive prices. To meet that objective, ABC bank is developing an activity-based cost system for its cashier department which is part of the retail banking division. A task force has identified five different activities: (1) the processing of deposits, (2) the processing of withdrawals, (3) answering customer inquiries, (4) selling negotiable instruments, and (5) the balancing of cash registers. By tracing the costs of operating the cashier department to these five activities, the task force has compiled the following information regarding support costs and activities for one of its branches: Support Activity Estimated Cost Quantity Processing deposits (44.445 49.875 Processing withdrawals E39,120 34.125 Answering inquiries E37,290 67.500 Selling negotiable instruments $7.290 1,650 Balancing cash registers E6.435 1.950 (134,580 The task force has developed the following list of activities which are undertaken in connection with the "Retirement Plus Account", a current account product marketed to retired persons: Support Activity Average monthly volume per current account Processing deposits 3.5 Processing withdrawals 6.5 Answering inquiries 3.1 Selling negotiable instruments 1.0 Required: (a) Calculate the total monthly support costs for the "Retirement Plus Account" product