Heartsaver First Aid Part I Progress Indicator: Question 4 of 22 4.  When diesel fuel is transferred by means of a pump and a hose equipped with a nozzle containing a self-closing valve, a powered pump may be used only if: Choices: The hose is equipped with a nozzle containing a self-closing valve without a latch-open device The pump is equipped with an accessible emergency shut-off switch Both a and b Neither a nor b