Which blood vessels have the smallest diameter ?

Options

A. Capillaries
B. Arterioles
C. Venules
D. Lymphatic

Explanation

**Step-by-Step Solution:**

1. **Identify the Blood Vessels**: We need to determine which blood vessels are being compared in terms of diameter. The main types of blood vessels are capillaries, arterioles, venules, and lymphatics.

2. **Examine the Diameter of Each Vessel**:
- **Capillaries**: The diameter of capillaries is approximately 8-10 micrometers. They are the smallest blood vessels in the body.
- **Arterioles**: Arterioles have a diameter of less than 100 micrometers. They are larger than capillaries.
- **Venules**: Venules have a diameter of about 7-10 micrometers. They are slightly larger than capillaries but can vary.
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