Assertion: Black hole is called so because it is black in colour.
Reason: The gravitational pull of black hole is such that, nothing escapes from it.

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 both assertion is false and reason is true.

Answer

To analyze the assertion and reason provided in the question, we will break down the statements step by step.

### Step 1: Understand the Assertion
The assertion states: "Black hole is called so because it is black in colour."
- This statement is misleading. While black holes do not emit light and appear black, their name does not derive from their color. Instead, they are called "black holes" because they are regions in space where gravity is so strong that nothing, not even light, can escape from them.

### Step 2: Understand the Reason
The reason states: "The gravitational pull of a black hole is such that nothing escapes from it."
- This statement is true. Black holes have an incredibly strong gravitational pull due to their dense mass concentrated in a small volume. This gravitational force is so strong that it prevents anything, including light, from escaping once it crosses a certain boundary known as the event horizon.

### Step 3: Evaluate the Relationship Between Assertion and Reason
- The assertion is incorrect because the name "black hole" does not come from its color. The reason is correct as it accurately describes the nature of black holes and their gravitational pull.
- Since the reason does not provide a valid explanation for the assertion, we conclude that the assertion is false while the reason is true.

### Conclusion
Based on the analysis:
- Assertion: False
- Reason: True

The correct answer to the question is that the assertion is incorrect, but the reason is correct.