What is the correct sequence of the parts of the small intestine?

• A
  Duodenum $\rightarrow$ Jejunum $\rightarrow$ Ileum
• B
  Duodenum $\rightarrow$ Ileum $\rightarrow$ Jejunum
• C
  Ileum $\rightarrow$ Jejunum $\rightarrow$ Duodenum
• D
  Jejunum $\rightarrow$ Ileum $\rightarrow$ Duodenum