Sub aerial vegetative propagation:
Sub aerial vegetative propagation is a type of asexual reproduction in plants where new individuals are produced through the growth and development of vegetative structures above the ground. This method allows plants to reproduce without the need for seeds or flowers, and it is common in many plant species.

Examples of sub aerial vegetative propagation:
1. Suckers: Suckers are shoots that arise from the base of the stem or root of a plant. They grow horizontally underground and then emerge above the surface as new shoots. Suckers have their own root system and can develop into independent plants. Examples of plants that reproduce through suckers include banana plants and raspberry bushes.

2. Offsets: Offsets are small lateral shoots that develop from the base of the parent plant. They grow horizontally on or just below the soil surface and eventually become independent plants. Examples of plants that produce offsets include spider plants and many species of ferns.

3. Runners: Runners, also known as stolons, are long stems that grow horizontally above the ground, producing nodes and roots at regular intervals. At each node, new shoots can develop and grow into separate plants. Examples of plants that reproduce through runners include strawberry plants and some grass species.

Explanation:
Option D, bulbils, is not an example of sub aerial vegetative propagation. Bulbils are small bulb-like structures that develop in the leaf axils of certain plants. They are similar to bulbs in structure and function but are not produced above the ground. Instead, bulbils are usually formed on the aerial parts of the plant, such as the stem or leaves. Bulbils can detach from the parent plant and grow into new plants, but they are not considered as sub aerial vegetative propagation because they do not develop above the ground.

In summary, while suckers, offsets, and runners are all examples of sub aerial vegetative propagation, bulbils are not. Bulbils are produced on the aerial parts of the plant and do not develop above the ground.