Micropropagation can be achieved by

The correct option is Tissue culture.

Step-by-step Explanation:

1. Understanding Micropropagation:
Micropropagation is an advanced biotechnological technique used to rapidly multiply stock plant material to produce a large number of genetically identical progeny plants (clones) in a short duration. It is widely applied in agriculture, horticulture, and forestry for propagating disease-free plants and multiplying rare species.

2. The Principle of Tissue Culture:
Plant tissue culture is the laboratory method that enables micropropagation. The process involves taking a small portion of a plant (referred to as an explant), such as a cell, tissue, or organ, and placing it onto a sterile nutrient culture medium. Under controlled, aseptic laboratory conditions, the cells in the explant divide and differentiate into complete, independent plantlets, which can later be transferred to soil.

3. Comparing the Options:
• Self-pollination: This is a sexual reproduction process involving the transfer of pollen grains, which leads to genetic recombination and variation, rather than the clonal duplication achieved in micropropagation.
• Asexual reproduction & Vegetative propagation: These are broad, natural biological terms. While micropropagation is a form of asexual vegetative propagation, "Tissue culture" is the specific scientific technique and medium through which micropropagation is actively performed and achieved in practice.