*Question G0B07:
Which of these choices should be observed when climbing a tower using a safety harness?*  

*Correct Answer is  B: Confirm that the harness is rated for the weight of the climber and that it is within its allowable service life*  

### AI Response: (may contain errors)  

When climbing a tower using a safety harness, safety is paramount. Let's break down the choices:

### Correct Answer: 
**B: Confirm that the harness is rated for the weight of the climber and that it is within its allowable service life.**

- **Explanation**: 
  - A safety harness must be rated for the climber's weight to ensure it can support them without failure. 
  - Additionally, harnesses have a service life, which is the period during which they are safe to use. Using a harness beyond its service life can lead to material degradation, increasing the risk of failure.

### Why the Other Choices are Incorrect:

- **A: Always hold on to the tower with one hand**  
  - **Explanation**: While it is good practice to maintain three points of contact (two hands and one foot, or two feet and one hand) for stability, this choice is not comprehensive. It does not address the critical aspect of harness safety.

- **C: Ensure that all heavy tools are securely fastened to the harness**  
  - **Explanation**: While securing tools is important to prevent them from falling, this choice does not address the fundamental safety of the harness itself. It is possible to have secure tools but still be at risk if the harness is not rated or in good condition.

### Summary:
- The most critical aspect of climbing safety is ensuring that the harness is appropriate for the climber's weight and is not expired. 
- Always prioritize checking the harness before climbing, as it directly affects your safety.

### Rules of Thumb:
- **Three Points of Contact**: Always maintain three points of contact when climbing.
- **Harness Inspection**: Regularly inspect your harness for wear and ensure it is within its service life.
- **Weight Rating**: Always check the weight rating of your harness before use.