Correct option (A) stem or leaf
Explanation:
In plant tendril is a modification of stem, leaves or petiole with a thread like coiled shape. Function of tendril is for support, climbing, attachment, cellular invasion by parasitic plant.
Example : Leaves modified into tendril in pea for climbing.
Stem tendril which develop from axillary bud in cucumber, pumpkins, watermelon and grapevines for climbing.
