The most common form of locomotion in "fish" (in a paraphyletic sense) are "lateral undulations." In general (e.g. focus on the "anguilliform" variety), this specific form of locomotion involves alternating contractions of the muscles in which of the following regions of the body? (Select all that apply.)

a. Caudal peduncle
b. Paired fins
c. Snout
d. Trunk
e. All of the above
f. None of the above