Deficiency symptom appears first in young leaves if the soil is deficient in:

Options

A. CI
B. Mg
C. Ca
D. S

Answer

To solve the question regarding which nutrient deficiency symptoms appear first in young leaves, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Nutrient Mobility**:
- Nutrients can be classified based on their mobility within the plant. Mobile nutrients are those that can be easily moved from older tissues to younger tissues, while immobile nutrients remain in the tissues where they were originally deposited.

2. **Identify the Types of Nutrients**:
- **Mobile Nutrients**: These include elements like nitrogen, phosphorus, and potassium. Deficiency symptoms for these nutrients typically appear first in older leaves because the plant reallocates these nutrients to newer growth.
- **Immobile Nutrients**: These include elements like calcium, sulfur, and magnesium. Deficiency symptoms for these nutrients appear first in younger leaves since they cannot be moved from older tissues.

3. **Analyze the Given Options**:
- The options provided are:
1. Chlorine
2. Magnesium
3. Calcium
4. Sulfur
- Among these, we need to identify which ones are immobile.

4. **Determine the Correct Answer**:
- **Sulfur** is an immobile element, meaning its deficiency symptoms will appear first in young leaves.
- **Magnesium** and **Calcium** are also considered immobile to some extent, but sulfur is the most commonly recognized element that shows deficiency symptoms first in young tissues.
- **Chlorine** is a mobile nutrient, so its deficiency symptoms would appear in older leaves.

5. **Conclusion**:
- Therefore, the correct answer is **Sulfur**.

### Final Answer:
Deficiency symptoms appear first in young leaves if the soil is deficient in **Sulfur**.