The hind leg of a kangaroo is a long and powerful structure that is specialized for hopping and jumping, so it is most likely to be similar in structure and size to other hind legs that are adapted for similar types of movements. From the options given, the measurement that is most likely to be from an adult animal with a hind leg that is homologous to the kangaroo hind leg is:
- a bullfrog leg 30 cm long
This is because bullfrogs are known for their powerful legs, which they use for jumping and swimming. The length of 30 cm is also more comparable to the size of a kangaroo hind leg than the other options.