You are given:

- a 2½-gallon container full of water;
- an empty 1-gallon container;
- a 1½-pound weight;
- a 2½-pound weight;
- a 4½-pound weight;
- a 6½-pound weight; and
- a 2-pan balance.

 Each container weighs five pounds. A pint of water weighs one pound. One of the weights is slightly inaccurate - either lighter or heavier than the weight indicated above. Which weight is inaccurate and in which direction:

 A. can be determined in three weighings.

B. can be determined in four weighings.

C. can be determined as to which weight in two weighings, but which direction it is off cannot necessarily be determined.

D. can be determined as to which weight in three weighings, but which direction it is off cannot necessarily be determined.

E. cannot be determined from the given conditions.