During the winter months when it is cold the internet works at full speed. The network administrator notices that during the summer months when the temperature increases, the speed of the network gets slow. After inspecting the router, they record a temperature of 150 degrees Fahrenheit. The label on the router states that it must be kept in temperature below 40 degrees Fahrenheit. This is an example of what?

irregular operating parameters
increase in humidity outside
poor internal network design
spontaneous electrical fluctuation