The correct option is A Layering
Layering is a means of plant propagation in which a portion of an aerial stem grows roots while still attached to the parent plant and then detaches as an independent plant.
Twin scaling is a method of propagating plant bulbs.
A cutting is a vegetative plant part which is severed from the parent plant in order to regenerate itself, thereby forming a whole new plant.
Micropropagation is the practice of rapidly multiplying stock plant material to produce a large number of progeny plants, using modern tissue culture methods.
Thus, the correct answer is option (A), 'Layering'.