The COD of a water sample is found to be 30 mg of O₂ per liter. What volume of 0.0020 M K₂Cr₂O₇ will be required to titrate a 50-ml sample of the water?
A) 3.75 mL
B) 7.50 mL
C) 15.00 mL
D) 30.00 mL