Statement I: A raindrop after failing through some height attains a constant velocity.
Statement II: At constant velocity, the viscous drag is just equal to its weight.

Options

A. Statement I is true, statement II is true and Statement II is a correct explanation for Statement I.
B. Statement I is true, Statement II is true and Statement II is NOT the correct explanation for Statement I.
C. Statement I is true, Statement II is false.
D. Statement I is false, Statement II is true.

Explanation

To solve the question, we need to analyze both statements and determine their validity.

### Step-by-Step Solution:

1. **Understanding Statement I**:
- The first statement claims that a raindrop, after falling through some height, attains a constant velocity. This is known as terminal velocity.
- As the raindrop falls, it accelerates due to gravity until the forces acting on it balance out.

**Hint**: Consider the forces acting on the raindrop as it falls.

2. **Forces Acting on the Raindrop**:
- The forces acting on the raindrop include its weight (downward force due to gravity) and the viscous drag (upward force due to air resistance).
- Initially, the weight is greater than the viscous drag, causing the raindrop to accelerate downward.

**Hint**: Think about how the raindrop's speed changes as it falls.

3. **Reaching Terminal Velocity**:
- As the raindrop continues to fall, the speed increases, which increases the viscous drag until it equals the weight of the raindrop.
- At this point, the net force acting on the raindrop becomes zero, and it stops accelerating, thus moving at a constant velocity.

**Hint**: What happens to the forces when the raindrop reaches a constant speed?

4. **Understanding Statement II**:
- The second statement claims that at constant velocity, the viscous drag is just equal to the weight of the raindrop.
- This is indeed true because, at terminal velocity, the upward force (viscous drag) balances the downward force (weight).

**Hint**: Reflect on the relationship between forces at constant velocity.

5. **Conclusion**:
- Since Statement I is true (a raindrop does attain a constant velocity), and Statement II is also true (at constant velocity, the viscous drag equals the weight), both statements are correct.
- Therefore, the correct conclusion is that both statements are true.

### Final Answer:
Both Statement I and Statement II are true.