Bryophyllum daigremontianum is characterized, by the formation of
(a)Plantlets in leaf notches while attached to the plant.
(b)Plantlets from marginal notches when the leaf falls on the ground.
(c)Buds in the marginal notches of leaves.
(d)Plantlets on the leaves in the region of injury.

Hint: Bryophyllum daigremontianum shows vegetative propagation by stem and leaves. Bryophyllum appears to be arrested during the stage of the embryonic until favourable condition.

Complete answer:
Bryophyllum daigremontianum and begonia show vegetative propagation. The vegetative propagation is a type of asexual reproduction. The new small buds arise from the margin of the leaves in Bryophyllum and grow to a new plant. The Bryophyllum daigremontianum is characterized by the leaf notches while attached to the plants.

Additional Information: -Plants reproduce by sexual reproduction, wherein the flowering plant produces male and female gametes fertilize which grows into seeds within the fruit and the other is asexual reproduction where no fertilization of male and female gametes takes place but plant reproduce by budding, fragmentation, spore formation.
-In asexual reproduction when the plants reproduce by the vegetative part of the mother plant give rise new plant.
-Bryophyllum daigremontianum shows vegetative reproduction by leaves where the new buds are arises from the margin of the leaves and germinate under the favourable condition when falling on the ground
-Bryophyllum daigremontianum is a perennial i.e. the lifespan of Bryophyllum daigremontianum is more than two years.
-Bryophyllum daigremontianum has modified leaves i.e. leaf- stem combination called phylloclades which can produce bulblets.

So, the correct answer is ‘Plantlets in leaf notches while attached to the plant.’

Note: -Bryophyllum daigremontianum is also known as cathedral bells, life plants, air plants, miracle plant is a native plant in Madagascar.
-Bryophyllum daigremontianum can cause cardiac poisoning mainly in grazing animals.
-Bryophyllum means growing of leaf from ‘bryein’ means to grow and ‘phyllon’ means leaf.