The correct option is B tendril
A tendril is a modified leaf, stem or petiole. It is a sensitive thread-like structure that can coil around a support. It is present in climbing plants.
The spine is technically a modified, sharp-pointed leaf. Since it has a bud in its axil, the spine occurs in the relative position of a leaf.
A cladode is a stem that is modified into a leaf-like structure for photosynthesis.
A hook is a structure for hanging plants on a porch.