20 voltsis the extent ESD sensitive components can be damaged and every other option is wrong. ESD sensitive components can be damaged by as little as 20 volts.
ESD (electrostatic sensitive device) is any electrical component that can be damaged by static charges. People working such devices usually wear or work with ESD protective materials like grounding mat, antistatic garments or anti static wrist strap to prevent the device from getting damaged as it is known that static charges that build up on people, tools and several non conductors or semi conductors can damage the device.
ESDs are electrostatic-sensitive devices that are damaged by static and charges. This build-up of static can lead to the damage of the ESDs. Some devices that have electrostatic-sensitive devices are computer cards and laser diodes. When dealing or handling items with electrostatic sensitive devices, people should be careful. These items are electrical and anything can happen with electricity.
There are ways to shield yourself from the dangers of electrostatic sensitive devices. It is preferable that there is anti-static surrounding the ESD device. Even twenty volts can damage these ESD sensitive components. It may seem unusual that 20 volts can damage a device that is electrical because nine volts is not dangerous to the human body, but 60 volts would be somewhat dangerous.