Sequence of Operations for the Preparation of Clay:

1. Weathering:
The first step in the preparation of clay is weathering. Weathering refers to the process of exposing the clay to natural environmental conditions such as air, water, and sunlight. During weathering, the clay undergoes various physical and chemical changes. This process helps to break down large clay particles into smaller ones and also removes impurities and organic matter present in the clay.

2. Tempering:
After weathering, the clay is tempered. Tempering is the process of adding water to the clay and mixing it thoroughly. This step is essential to achieve the desired consistency and plasticity of the clay. Tempering makes the clay more workable and easier to shape. It also helps to distribute the moisture evenly throughout the clay, ensuring uniform drying and firing.

3. Cleaning:
Once the clay is properly tempered, it needs to be cleaned. Cleaning involves removing any remaining impurities, rocks, twigs, or other foreign materials from the clay. This is typically done by hand or using sieves and screens. Cleaning ensures that the clay is free from any unwanted substances that could affect its quality or performance during the clay processing and shaping stages.

4. Blending:
Finally, the cleaned clay is blended. Blending refers to the process of mixing different types or batches of clay together to achieve a consistent composition and desired properties. This step is important to ensure that the clay meets the specific requirements for its intended use. Blending can be done manually or using mechanical equipment such as pug mills or mixers.

The Correct Sequence:
The correct sequence of operations for the preparation of clay is as follows:

1. Weathering - The clay is exposed to natural environmental conditions to break down large particles, remove impurities, and organic matter.
2. Tempering - Water is added to the clay to achieve the desired consistency and plasticity.
3. Cleaning - Any remaining impurities or foreign materials are removed from the clay.
4. Blending - Different types or batches of clay are mixed together to achieve a consistent composition and desired properties.

Therefore, the correct sequence is option C) 3 1 4 2.