Low Oil Pressure on 44k Engine

Hey Guys,
Body of my has 2000 Sentra and the Low Oil light came up last couple of week, put a gauge to it very low, drop the Pan thing looks OK, not sure what to do????????? where is the oil pump??????? any ideals

Thanks
Mai
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oil pump is internal, should be under the motor sort of in the oil pan(but a little above and to the side, connected to that metal pipe with a screen on the end of it that sits in the oil pan(thats the oil pickup))

i dont mean to sound degrading, but low oil light, the car has enough oil? im just making sure of all points

ummm is the oil pan dented? that could restrict oil getting to the pickup.

otherwise oil pump is a good place to start.

I have him check all the abvious thing and all look ok, it's a Crank Driven Pumps or Shaft Driven???? can it be replace with the Engine in the Car??? or a crate motor is in need???