challenge: What is the Greek origin of the name 'Trachurus', the genus of Jack Mackerels and Saurels?
  
  A. Trachys meaning 'big' and oura meaning 'school'
  B. Trachys meaning 'strong' and oura meaning 'fin'
  C. Trachys meaning 'fast' and oura meaning 'swim'
  D. Trachys meaning 'rough' and oura meaning 'tail'
  Answer: 