Which of the following helmet is the safest helmet for riding bike?

You haven't provided a list of helmets to choose from. However, the safest helmet for riding a bike generally has the following features:

1. Certification: The helmet should be certified by recognized safety standards like DOT, SNELL, or ECE.

2. Material: The helmet should be made of high-quality material. The most common materials are polycarbonate, fiberglass composite, and carbon fiber.

3. Fit: The helmet should fit snugly on your head. It should not be too tight or too loose.

4. Coverage: Full-face helmets provide the most protection.

5. Visibility: The helmet should provide good visibility. It should not obstruct your peripheral vision.

6. Ventilation: Good helmets have proper ventilation systems to keep you cool and comfortable.

7. Comfort: The helmet should have a comfortable lining. It should not cause discomfort during long rides.

8. Retention system: The helmet should have a reliable retention system. The chin strap should be easy to fasten and release.

Remember, the most expensive helmet is not necessarily the safest. The key is to find a helmet that fits well and meets safety standards.