Different microscopic organisms cause different diseases. When a dangerous microscopic organism is transferred from one person to many people, the disease it carries will spread. Why is this considered a theory instead of a hypothesis or a law?

A - It is a statement of fact about how nature works instead of an explanation.
B - It provides an explanation for many observations and accepted hypotheses.
C - It describes how to test a possible explanation of one specific relationship.
D - It has not changed over time even though new technology has been developed.