A cotyledon is a part of the embryo in a seed plant. The number of cotyledons is an important feature in classifying plants.
The mature seed in Pinus is composed of hard testa, thin tegmen, endosperm, embryo, and cap like perisperm. The embryo includes a short axis bearing ten cotyledons. Therefore, Pinus seeds have many cotyledons.

**Explanation:**

In Pinus seeds, there are *many cotyledons*.

**Cotyledons in Seeds:**
Cotyledons are structures found in the seeds of flowering plants (angiosperms) that serve as the primary storage and nutrient source for the developing embryo. They are the first leaves to emerge from the seed upon germination and play a vital role in the early growth and development of the plant.

**Number of Cotyledons in Seeds:**
The number of cotyledons present in seeds can vary depending on the type of plant. There are two main groups of plants based on the number of cotyledons they possess:

1. **Monocotyledons (Monocots):** These plants have seeds with a single cotyledon. Examples of monocots include grasses, lilies, orchids, and palms.

2. **Dicotyledons (Dicots):** These plants have seeds with two cotyledons. Examples of dicots include sunflowers, roses, beans, and oak trees.

**Cotyledons in Pinus Seeds:**
Pinus, commonly known as pine trees, are gymnosperms, which are a group of plants that produce seeds not enclosed within an ovary. Gymnosperms typically have seeds with multiple cotyledons, unlike angiosperms (flowering plants) which have one or two cotyledons.

In the case of Pinus seeds, which are found in the cones of pine trees, there are *many cotyledons*. These cotyledons are often thin and elongated, and they provide nourishment to the developing embryo within the seed.

It is important to note that the number of cotyledons in a seed is a characteristic feature used to classify plants into different groups. The presence of many cotyledons in Pinus seeds is one of the defining characteristics of gymnosperms, distinguishing them from angiosperms.

Overall, the correct answer to the question is option 'C' - Many cotyledons.