What Is the Relationship Between Crohn's Disease and Inflammatory Bowel

What is the relationship between Crohn's disease and inflammatory bowel disease?

A) Crohn's disease is one of the most common inflammatory bowel diseases.
B) Inflammatory bowel disease is a type of Crohn's disease.
C) They are two separate diseases but both affect only the colon.
D) In Crohn's disease, the colon is affected, but in inflammatory bowel disease only the small intestine is affected.
E) In Crohn's disease, small pouches form in the muscularis, while in inflammatory bowel disease, inflammation occurs throughout the digestive tract.