(A): The velocity of sound in hydrogen gas is more than the velocity of sound in oxygen gas.
(R): The density of hydrogen is more than the density of oxygen.

Options

A. Both 'A' and 'R' are true and 'R' is the correct, explanation of 'A'.
B. Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A'
C. A' is true and 'R' is false
D. Both 'A' and 'R' are false

Answer

To solve the question, we need to analyze both the statement (A) and the reason (R) given in the problem.

### Step 1: Understanding the Statement (A)
The statement (A) claims that "The velocity of sound in hydrogen gas is more than the velocity of sound in oxygen gas."

### Step 2: Understanding the Reason (R)
The reason (R) states that "The density of hydrogen is more than the density of oxygen."

### Step 3: Analyzing the Relationship Between Velocity and Density
The velocity of sound in a gas is given by the formula:
\[ V = \sqrt{\frac{\gamma P}{\rho}} \]
Where:
- \( V \) is the velocity of sound,
- \( \gamma \) is the adiabatic index (ratio of specific heats),
- \( P \) is the pressure,
- \( \rho \) is the density of the gas.

From this formula, we can see that the velocity of sound is inversely proportional to the square root of the density (\( \rho \)). This means that if the density increases, the velocity of sound decreases.

### Step 4: Comparing Densities of Hydrogen and Oxygen
It is known that the density of oxygen is significantly higher than that of hydrogen. Specifically, the density of oxygen is about 16 times greater than that of hydrogen.

### Step 5: Conclusion on the Statements
Since the density of hydrogen is less than the density of oxygen, it follows that the velocity of sound in hydrogen must be greater than that in oxygen. Therefore, statement (A) is true.

However, statement (R) is false because it incorrectly states that the density of hydrogen is greater than that of oxygen.

### Final Answer
Based on our analysis:
- Statement (A) is true.
- Statement (R) is false.

Thus, the correct option is:
**Sarsan is true and region is false.**

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