When soldering or working with CMOS electronics products or equipment, a wrist strap:

A wrist strap is an essential tool when working with CMOS electronics to protect sensitive components from static electricity. The correct answer emphasizes that the wrist strap must have less than 100,000 ohms of resistance. This specification is important because it ensures a safe discharge of static electricity to ground while preventing excessive current from flowing through the wrist strap, which could damage the electronic components or harm the user.

A wrist strap with this level of resistance is effective in mitigating the buildup of static charge by providing a controlled path to ground. If the resistance were too high, it could allow static to accumulate on the person's body, increasing the risk of an electrostatic discharge (ESD) event when touching delicate electronic parts. Conversely, a strap with little to no resistance would not appropriately ground the user, creating safety hazards and risking damage to the electronics due to uncontrolled discharges.

The other options provided do not accurately reflect the necessary specifications for a safe and effective wrist strap. For example, the requirements involving rubber material or a lack of resistance are not suitable for ESD protection. Maintaining the appropriate resistance is critical for ensuring safety and protecting electronics in a working environment.