[
  "Work forward from the total 1500 ml. First find how much was drunk in the morning, then find the remainder, then find 7/12 of that remainder.",
  "Morning: 2/5 x 1500 = 600 ml. Remainder = 1500 - 600 = 900 ml.",
  "Afternoon: 7/12 x 900 = 525 ml. Answer: 525 ml (option C)."
]