Which of the following statements is/are correct?
I. Thermometer is read by holding its bulb. II. A few sharp jerks are given to clinical thermometer before using it. III. Black fabric is preferred during winter. IV. Shopkeepers selling ice blocks usually cover them with jute sacks.

Options

A. I only
B. II and III only C
C. III and IV only
D. II, III and IV only

Explanation

To determine which of the statements is/are correct, let's analyze each one step by step.

### Step 1: Analyze Statement I
**Statement I:** Thermometer is read by holding its bulb.

- **Explanation:** This statement is incorrect. A thermometer should be held by the body (the upper part) and not by the bulb. Holding the bulb can affect the reading due to the heat from your hand.

### Step 2: Analyze Statement II
**Statement II:** A few sharp jerks are given to clinical thermometer before using it.

- **Explanation:** This statement is correct. Clinical thermometers often require a few sharp jerks to ensure that the mercury (or alcohol) inside the thermometer is brought down to a lower level before taking a new reading.

### Step 3: Analyze Statement III
**Statement III:** Black fabric is preferred during winter.

- **Explanation:** This statement is correct. Black fabric absorbs more heat compared to lighter colors, making it preferable in winter to keep warm.

### Step 4: Analyze Statement IV
**Statement IV:** Shopkeepers selling ice blocks usually cover them with jute sacks.

- **Explanation:** This statement is correct. Jute sacks are used to cover ice blocks as they provide insulation, helping to slow down the melting process by reducing heat transfer.

### Conclusion
Based on the analysis:
- Statement I: Incorrect
- Statement II: Correct
- Statement III: Correct
- Statement IV: Correct

Thus, the correct statements are II, III, and IV.

### Final Answer
The correct statements are II, III, and IV.

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