单项选择题
A.What is this customers address?
B.Does this customer have any unpaid bills?
C.What is the balance in this customers account?
D.What are the total sales for each of the last 6 months?
单项选择题 Which of the following tools is used to view historical information about tasks, database changes, messages, and notifications?（）
单项选择题 Which of the following describes the model used by the Geodetic Extender?（）
单项选择题 Which of the following best describes the age of the data in an OLTP system?（）