An accounting clerk for Christopher's Cheesecakes does not have access to the salary information for individual employees but wanted to know the salary of a new hire. He pulled total payroll expenses for the pay period before the new person was hired and then pulled the same expenses for the following pay period. He computed the difference between those two amounts to determine the individual's salary. What type of attack occurred?

A. Aggregation
B. Data diddling
C. Inference
D. Social engineering

Answer: C. Inference