The Muscularis Externa Contains Which of the Following Muscle Groups

Multiple Choice

The muscularis externa contains which of the following muscle groups?

A) an outer longitudinal layer that requires neural input for contraction
B) a muscularis mucosae, which lubricates as it contracts
C) an inner circular layer capable of slow -wave potentials only
D) both an inner circular and an outer longitudinal layer
E) an inner circular and outer longitudinal layer, and a muscularis mucosae