The correct answer is option 'A' - Scutellum.

The wheat grain, like other cereal grains, has an embryo inside it. The embryo is the young plant that is enclosed within the seed. It consists of different parts, including the cotyledon. The cotyledon is an essential part of the embryo as it stores and provides nutrients to the developing plant until it can perform photosynthesis on its own. In the case of wheat, the cotyledon is known as the scutellum.

Explanation:

The cotyledon is the part of the embryo that is responsible for storing and providing nutrients to the developing plant. It is the first leaf-like structure that emerges from the seed upon germination. The number and shape of cotyledons vary among different plant species.

In the case of the wheat grain, the embryo has one large, shield-shaped cotyledon known as the scutellum. The scutellum is located on one side of the embryo and is usually yellowish-white in color. It is easily visible when the seed is split open.

The scutellum plays a crucial role in the early growth and development of the wheat plant. It absorbs nutrients from the endosperm, which is the starchy tissue surrounding the embryo. These nutrients are then transported to the growing parts of the plant.

During germination, the scutellum swells and secretes enzymes that break down the endosperm, releasing stored starches, proteins, and other nutrients. These nutrients are then absorbed by the scutellum and transported to the developing shoot and root system of the plant.

Once the seedling emerges from the soil, the scutellum gradually withers and becomes non-functional. At this stage, the young plant is capable of performing photosynthesis and obtaining nutrients from the soil through its roots.

In summary, the wheat grain has an embryo with one large, shield-shaped cotyledon known as the scutellum. The scutellum is responsible for storing and providing nutrients to the developing wheat plant during germination until it can perform photosynthesis on its own.