The correct option is D
(a) and (b) above.
Volume of water that can be filled in the bottle = 250 mL
Volume of water poured into the tumbler = 250 mL × 6 = 1500 mL
It's given that the tumbler is half filled now, which means,
Capacity of the tumbler ÷ 2 = 1500 mL
=> Capacity of the tumbler = 1500 mL × 2 = 3000 mL
Since 1000 mL = 1L,
Capacity of the tumbler = 3000 ÷ 1000 = 3 L