The below Pareto chart indicates defects in areas associated with billing a client for project services. Based on this Pareto analysis, which area, or areas, indicate the greatest opportunity for improvement?

a. The account number, because if it is incorrect, the invoice may be sent to the wrong client.

b. The daily rate, because if it is incorrect, the total amount of the invoice will be wrong, which impacts the cash flow.

c. The charge code, name, address, receipt date, pvc code, discount amount, mail date, and phone number, because they are fairly easy to confirm and correct, thereby significantly reducing the types of defects.

d. The account number and daily rate, because they account for 80 percent of all defects.

Number of Defects Account Number Daily Rate Charge Code Name Defect Type Address Receipt Date PVC Code Discount Amount Mail Date Phone Number