The correct answer is A) Setting the squelch control to its maximum level. Setting the squelch control to its maximum level can result in limited receiving range because the squelch function is designed to suppress background noise when the received signal is weak. When the squelch is set to maximum, it can effectively block out weaker signals, reducing the overall receiving range of the GMDSS equipment. The other options are incorrect because: B) Setting the squelch control to its minimum level would not limit the receiving range, as it would allow all signals to be received; C) Setting the channel selection switch between channels would not affect the receiving range; and D) The power switch being set to "high" output would not result in receiver overloading, as this would typically increase the receiving range.