The correct options are
A Provide protection and climbing
B Help in photosynthesis
C Help in vegetative propagation
In certain plants, the aerial stem or buds get modified to perform special functions like climbing, protection, food storage, vegetative propagation etc. Stem or its branches get modified into green thread like leafless structures called tendrils which are meant for climbing. Thorns are used as organs of defence or climbing (e.g. Bougainvillea) and check transpiration. Phylloclades are fleshy, green flattened or cylindrical branches of unlimited growth. They take part in photosynthesis and store water. Bulbils are modified vegetative or floral buds with stored food and meant for vegetative propagation.