technician a says a refrigerant identifier is only needed when the technician is unsure of the refrigerant used in an ac system. technician b says that some refrigerant identifiers can measure the amount of moisture in the refrigerant system to aid in diagnosis. who is  correct?  
a.  technician a   
b.  technician b   
c.  both technicians a and b   
d.  neither technicians a nor b

19838483818838484849 pieces of wood.

But isn’t this a question asking ur opinion this is something about u. ( well i would pick somewhat true bc that’s what i do when i don’t know what to choose ) hopefully this =“)

Which of the following is an example of an opposing signal? no examplthates given.   i would say, that traffic lights in a city at major intersections direct the flow of traffic in opposite directions so would be an example.also, stop signs on either side of the same street would be an example. at a train crossing, the light for allowing car traffic in opposite directions or not would be another example.