challenge: What is the meaning of the Bengali idiom 'Koi machher pran'?
  
  A. It symbolizes the resilience of Koi fish to survive out of water
  B. It is a phrase used to describe the beauty of Koi fish
  C. It describes the ability of Koi fish to thrive in water
  D. It refers to the short lifespan of Koi fish
  Answer: 