A mother brings her nine year-old son to your office, along with the snake that bit him 20 minutes earlier. Which of the following, if identified during your examination of the snake, is most suggestive that the snake is poisonous?
A. elliptical pupils
B. a rounded head
C. a double row of caudal plates
D. the length of the snake
E. the presence of a black band next to a red band