The correct answer is A. A little.
The other options are incorrect because they do not accurately describe the amount of water in the jug. Option B, A few, is incorrect because it implies that there were only a small number of drops of water in the jug. Option C, Many, is incorrect because it implies that there was a large amount of water in the jug. Option D, Little, is incorrect because it implies that there was no water in the jug.
The amount of water in the jug is not explicitly stated in the question, but it can be inferred from the fact that the crow survived. If there was no water in the jug, the crow would have died. Therefore, it is reasonable to conclude that there was at least a little bit of water in the jug.