The food chain that is not contained within the food web is:
2. Leaves > Lady bug > Mouse > Fox
This is because ladybugs primarily feed on aphids and other small insects rather than leaves. The presence of a mouse directly after a ladybug in this chain does not make ecological sense, as the ladybug does not serve as a direct food source for the mouse.
The other options (1, 3, and 4) present more plausible food chains that align logically with typical relationships in a food web.