[tlhIngan Hol] yuQ Suv Duj 'ar or yuQ luSuv Duj 'ar ?

This must be pretty straightforward, but I'll ask anyway. Recently, we'd been given the following examples, with regards to how the construction {noun 'ar}, is to be treated, i.e. singular or plural. Duj 'ar DIlegh ? bIQ 'ar wIlegh ? So, if the questioned object is countable, then we use a plural prefix. But does the opposite apply too ? If we have a questioned subject which is countable, then do we again use a plural prefix ? Should one say {yuQ Suv Duj 'ar} or {yuQ luSuv Duj 'ar} ? I'm pretty sure it must be {yuQ luSuv Duj 'ar}, but I'd like to make certain. ~ mayqel qunen'oS