During hot sunny weather, test personnel performing a bubble leak test outdoors should:

do all testing at night so all spontaneous radiation will not endanger workers or test personnel.

apply several coatings of test solution so that the heavy coating of solution will evaporate slower.

limit coverage of the test surface with solution film to an area of such size that it can be tested before the detector solution dries or evaporates from the surface of the metal.

none of the above.