Mendel utilised ................. which had undergone .......... and demonstrate the stable trait inheritance for several generations.

Options

A. Cross breeding, Cross pollination
B. True breeding line, autogamy
C. Hybridisation, Cross pollination
D. None of these

Explanation

To answer the question, we need to identify what Mendel utilized in his experiments and what characteristic these entities had undergone to demonstrate stable trait inheritance over several generations.

### Step-by-Step Solution:

1. **Identify Mendel's Key Focus**: Mendel is known for his work with pea plants (Pisum sativum), where he studied the inheritance of traits.

2. **Understanding True Breeding Lines**: True breeding lines refer to plants that, when self-pollinated, produce offspring that are identical to themselves for specific traits. This means that these plants have undergone continuous self-pollination.

3. **Recognizing the Process of Pollination**: Mendel performed artificial pollination, which involved emasculation (removing the male parts of the flower) to prevent self-pollination and allow for controlled cross-pollination between different true breeding lines.

4. **Stable Trait Inheritance**: The true breeding lines Mendel used demonstrated stable inheritance of traits across several generations, meaning that the traits remained consistent when these lines were self-pollinated.

5. **Conclusion**: Based on the above points, Mendel utilized true breeding lines that had undergone continuous self-pollination to demonstrate stable trait inheritance for several generations.

### Final Answer:
Mendel utilized **true breeding lines** which had undergone **self-pollination** and demonstrated stable trait inheritance for several generations.