The segments that lack nephridiopores are 

Options

A. first 2
B. last 2
C. clitellae segments
D. none

Answer

To solve the question about the segments that lack nephridiopores in an earthworm, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Earthworm**:
- Earthworms have a segmented body structure, which is known as metameric segmentation. Each segment contains various organs, including excretory structures.

**Hint**: Remember that earthworms are segmented organisms with specific functions assigned to each segment.

2. **Identify Nephridia**:
- Nephridia are the excretory structures in earthworms. They are coiled tubular structures that help in the excretion of waste. The openings of these structures are called nephridiopores.

**Hint**: Think of nephridia as the kidneys of the earthworm, responsible for waste removal.

3. **Locate Nephridiopores**:
- Nephridiopores are present in almost all segments of the earthworm, but there are exceptions.

**Hint**: Focus on which segments might not have these openings.

4. **Determine the Segments Without Nephridiopores**:
- It is known that the first two segments of the earthworm do not have nephridiopores. This means that these segments lack the openings for the excretory structures.

**Hint**: Recall that the first two segments are often special in many organisms, including earthworms.

5. **Evaluate the Options**:
- Option 1: First 2 segments (Correct)
- Option 2: Last 2 segments (Incorrect, as these segments do have nephridiopores)
- Option 3: Clitellar segments (Incorrect, as these segments have the most nephridia)
- Option 4: None of these (Incorrect, as the first two segments do not have nephridiopores)

**Hint**: Analyze each option based on the information about nephridiopores.

### Final Answer:
The segments that lack nephridiopores are the **first two segments** of the earthworm.