What will happen if one fails to install a memory saver before disconnecting the battery?

When disconnecting the battery from a vehicle, if a memory saver is not installed, various electronic settings may be lost, including the radio presets. The vehicles today often have numerous electronic components that rely on an uninterrupted power supply to retain their configurations. This includes the radio, clock, and other memory settings.

When the battery is disconnected, it disrupts the power supply to these components, leading to a reset of their settings once power is restored. A memory saver is a tool that provides constant power to these systems while the battery is disconnected, preventing loss of saved settings. Thus, failing to use a memory saver will indeed result in the loss of radio settings, making this the correct answer.