challenge: What is a distinctive feature of the veins in the hindwings of Hypenagonia?
  
  A. Veins 2 and 3 are stalked, while veins 4 and 5 are separate
  B. Veins 3 and 4 are stalked, while veins 5 and 6 are separate
  C. Veins 3, 4 and 6, 7 are stalked, whereas vein 5 is from near lower angle of cell
  D. Veins 1 and 2 are stalked, while veins 3 and 4 are separate
  Answer: 