Aggregation is the act of obtaining information of a higher sensitivity by combining information from lower levels of sensitivity.
The incorrect answers are:
Polyinstantiation is the development of a detailed version of an object from another object using different values in the new object.
Inference is the ability of users to infer or deduce information about data at sensitivity levels for which they do not have access privilege.
Data mining refers to searching through a data warehouse for data correlations.
Sources:
KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 7: Applications and Systems Development (page 261). KRUTZ, Ronald & VINES, Russel, The CISSP Prep Guide: Gold Edition, Wiley Publishing Inc., 2003, Chapter 7: Database Security Issues (page 358).