A data system is $\_\_\_\_.$

a$.$ a set of procedures and methods for the regular, planned collection, analysis, and presentation of information for use in making marketing decisions

b$.$ a display of relevant information sets designed to provide interactive access to a company's key metrics

c$.$ the part of a decision support system that includes all the routines that allow the user to manipulate the data so as to conduct the kind of analysis the individual desires

d$.$ the part of a decision support system that includes the processes used to capture and the methods used to store data coming from a number of external and internal sources