Cell organelle getting stained with redox dye Janus Green is

The correct option is B Mitochondrion

• Janus Green B is a basic and a redox dye which is primarily used to stain the cellular organelle mitochondria.
  
• Janus Green B changes the colour according to the availability of oxygen (redox dye).
• The indicator oxidizes to a blue colour in the presence of oxygen.
• So, the correct answer is 'Mitochondrion'.