Assertion : Humans cannot hear the sound of ultrasonic frequency.
Reason : Human ear can only hear sound of frequency range 20 Hz to 20000 Hz.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If assertion is false but reason is true.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that "Humans cannot hear the sound of ultrasonic frequency."

**Explanation**: Ultrasonic frequencies are defined as sound waves that have a frequency greater than 20,000 Hz. Since the human ear can only detect sounds within the frequency range of 20 Hz to 20,000 Hz, it follows that sounds above 20,000 Hz (ultrasonic sounds) are inaudible to humans.

### Step 2: Understand the Reason
The reason provided is "Human ear can only hear sound of frequency range 20 Hz to 20,000 Hz."

**Explanation**: This statement is true. The human hearing range is indeed from 20 Hz to 20,000 Hz. This means that any sound with a frequency below 20 Hz (infrasonic) or above 20,000 Hz (ultrasonic) cannot be heard by humans.

### Step 3: Evaluate the Relationship
Now, we need to determine if the reason correctly explains the assertion.

- The assertion is true because humans cannot hear ultrasonic frequencies.
- The reason is also true as it accurately describes the limits of human hearing.

Furthermore, the reason provides a correct explanation for the assertion since it clarifies why ultrasonic sounds are inaudible to humans.

### Conclusion
Both the assertion and the reason are true, and the reason is a correct explanation of the assertion.

### Final Answer
- Assertion: True
- Reason: True
- Explanation: The reason correctly explains why the assertion is true.

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