Given only one full 3-litre bottle and two empty ones of capacities 1 litre and 4 litres, all ungraduated, the minimum number of pourings required to ensure 1 litre in each bottle is:

Correct option is B

Solution:
Initial State:
3-litre bottle: Full (3 litres).
1-litre bottle: Empty (0 litres).
4-litre bottle: Empty (0 litres).
Step-by-Step Process to Get 1 Litre in Each Bottle:
Pour 3 litres from the 3-litre bottle into the 4-litre bottle.
3-litre bottle: Empty (0 litres).
4-litre bottle: 3 litres.
1-litre bottle: Empty (0 litres).
Pour 1 litre from the 4-litre bottle into the 1-litre bottle.
3-litre bottle: Empty (0 litres).
4-litre bottle: 2 litres.
1-litre bottle: Full (1 litre).
Pour 2 litres from the 4-litre bottle back into the 3-litre bottle.
3-litre bottle: 2 litres.
4-litre bottle: Empty (0 litres).
1-litre bottle: Full (1 litre).
Final State:
3-litre bottle: 1 litre remaining.
4-litre bottle: 1 litre.
1-litre bottle: 1 litre.
Total Pourings: Only 3 pourings are required to achieve the desired state.
Answer: (b) 3