A takes twice as much time as B and thrice as much time as C to finalise a task. Working together, they can complete the task in 8 days. The time (in days) taken by A, B and C, respectively, to complete the task is:

If A takes twice as much time as B and thrice as much time as C, then B is twice as fast as A, and C is thrice as fast as A. Let A's efficiency = 1 unit/day, then B = 2 units/day, C = 3 units/day. Combined efficiency = 6 units/day. Together they complete in 8 days, so total work = 48 units. A alone: 48/1 = 48 days, B alone: 48/2 = 24 days, C alone: 48/3 = 16 days. The ratio 48:24:16 matches option D.