**Vegetative Propagation in Plants**

Vegetative propagation is a method of plant reproduction where new plants are formed from vegetative parts of the parent plant, such as stems, leaves, and roots, without the involvement of seeds or spores. It is commonly used in horticulture and agriculture to propagate desirable plants with desirable traits.

There are several methods of vegetative propagation, and the correct answer to the question is option 'D', which states that all of the given methods (cutting, grafting, and layering) are ways of vegetative propagation. Let's explore each of these methods in detail:

**1. Cutting:**
Cutting involves taking a portion of a stem, leaf, or root from the parent plant and placing it in a suitable growing medium. The cutting develops roots and eventually grows into a new plant that is genetically identical to the parent plant. This method is commonly used for propagating plants like roses, geraniums, and mint.

**2. Grafting:**
Grafting involves joining a stem (scion) from one plant to the stem or root (rootstock) of another plant. The two plant parts are carefully connected and bound together until they heal and grow as a single plant. Grafting is commonly used to propagate fruit trees, such as apples and citrus, as it allows for the transfer of desirable traits from one plant to another.

**3. Layering:**
Layering involves bending a low-growing branch of a parent plant to the ground and covering it with soil while it is still attached to the parent plant. The buried portion of the branch develops roots, and once it is well-established, it can be separated from the parent plant and grown as an independent plant. This method is commonly used for plants like blackberries, raspberries, and strawberries.

All three methods mentioned above - cutting, grafting, and layering - are effective ways of vegetative propagation in plants. They allow for the production of new plants that are genetically identical to the parent plant, preserving desirable traits and characteristics. These methods are widely used in agriculture, horticulture, and gardening to propagate and multiply plants efficiently.