Which among the following is true ?

Options

A. Air is a bad conductor of heat and thermal expansion of solids is more than that of gases.
B. Air is a good conductor of heat and thermal expansion of solids is less than that of gases.
C. Air is a bad conductor of heat and thermal expansion of solids is less than that of gases.
D. Air is a good conductor of heat and thermal expansion of solids is more than that of gases.

Explanation

To solve the question "Which among the following is true?", we need to analyze the statements provided and determine their validity based on our knowledge of the properties of air, solids, and gases.

### Step-by-Step Solution:

1. **Understanding the Properties of Air**:
- Air is composed of molecules that are not in continuous contact with each other. This means that air does not transfer heat effectively.
- Therefore, the statement "Air is a bad conductor of heat" is true.

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