What is a theory

A)  the premise that knowledge should be acquired through logical reasoning 
B)  a statement of fact that describes a set of observations 
C)  the premise that knowledge should be acquired through observation 
D)  a system of interrelated ideas used to explain a set of observations

Interrelated Ideas

Concepts, thoughts, or topics that are connected or linked to each other in a significant manner.

Theory

A systematically organized set of concepts, explanations, and predictions about phenomena that seeks to clarify relationships or understand principles.

Observation

The active acquisition of information from a primary source using the senses or instruments that extend beyond natural sensory capabilities.