Refer to this portion of a dichotomous key for fish identification to answer the question. 1. (a) has a single dorsal fin ® 5 (b) has a double dorsal fin ® 2 5. (a) has small fin on back near tail ® 6 (b) has no fin on back near tail ® 7 6. (a) has barbs near the mouth ® catfish (b) does not have barbs near the mouth ® 10 according to this dichotomous key, any catfish must have a. a double dorsal fin, a small fin on the back near the tail, and barbs near the mouth. b. a single dorsal fin, no small fin on the back near the tail, and barbs near the mouth. c. a double dorsal fin, a small fin on the back near the tail, and no barbs near the mouth. d. a single dorsal fin, a small fin on the back near the tail, and barbs near the mouth.