Bronze Life Corporation (BLC) Manufactures Decorative, Sculpted Accessories That Are

Bronze Life Corporation (BLC) manufactures decorative, sculpted accessories that are sold by interior decorators and home furnishing stores. The following situation concerns two BLC employees: Deborah Philbun, head of the company's Billing Department, and Gary Bitner, the firm's general manager.
Philbun's Billing Department makes heavy use of hourly employees and is evaluated as a cost center. Understanding the need for prompt collection of receivables, Philbun strives to run a first-class operation. Philbun also understands the need to contribute in a big way to BLC's financial performance so she continually strives to minimize Billing Department expenses.
Unfortunately, Philbun experienced a heated discussion with Bitner several weeks ago, the subject being the shoddy operation that she is running. Bitner complained loudly about the lack of timely billings to customers and the general lack of attention to detail, as many complaints have surfaced about erroneous invoices and customer statements.
Required:
A. What is meant by the term "responsibility accounting?"
B. What measure(s) of performance would companies normally use to evaluate a cost-center manager?
C. Does Bitner have a valid reason to be upset with Philbun? Given the nature of the Billing Department, did Philbun err in her quest to minimize expenses? Explain.
D. Is it likely that the Billing Department could be evaluated as a profit center? Why?