The eye lens is a

Options

A. transparent double-convex lens
B. transparent double-concave lens
C. transparent concavo-convex lens
D. none of these

Answer

To answer the question "The eye lens is a...", we need to determine the type of lens that is present in the human eye. Let's analyze the options step by step.

### Step-by-Step Solution:

1. **Understanding the Eye Lens**:
- The eye lens is a crucial part of the eye that helps in focusing light onto the retina.

2. **Identifying Lens Types**:
- There are different types of lenses:
- **Convex Lens**: Thicker in the middle than at the edges, converges light rays.
- **Concave Lens**: Thinner in the middle than at the edges, diverges light rays.
- **Double Convex Lens**: Convex on both sides.
- **Double Concave Lens**: Concave on both sides.

3. **Evaluating the Options**:
- **Option 1: Transparent Double Convex Lens**:
- This type of lens is thicker in the middle and is used to converge light. This is indeed the type of lens found in the human eye.
- **Option 2: Transparent Double Concave Lens**:
- This lens diverges light and is not used in the eye.
- **Option 3: Transparent Concave or Convex**:
- This option suggests a lens that is concave on one side and convex on the other. This type of lens is not present in the eye.
- **Option 4: None of these**:
- Since we have identified the correct type of lens, this option is incorrect.

4. **Conclusion**:
- The correct answer is **Option 1: Transparent Double Convex Lens**. This is the type of lens that the eye uses to focus light.

### Final Answer:
The eye lens is a **Transparent Double Convex Lens**.