The entropy of a crystalline substance a absolute zero on the basis of the third law of thermodynamics should be taken as

Options

A. `100`
B. `50`
C. Zero
D. Different for different substance

Explanation

To solve the question regarding the entropy of a crystalline substance at absolute zero based on the third law of thermodynamics, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Third Law of Thermodynamics**: The third law of thermodynamics states that the entropy of a perfectly crystalline substance approaches zero as the temperature approaches absolute zero (0 Kelvin). This means that at absolute zero, a perfectly ordered crystalline substance has no randomness or disorder, leading to zero entropy.

2. **Defining Entropy**: Entropy (S) is a measure of the disorder or randomness in a system. For a crystalline substance, which has a highly ordered structure, the entropy is minimal at absolute zero.

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