Which of the following pumps are self-priming, and can deal with liquid from a level below the pump()<br /> (1) ejector<br /> (2) screw<br /> (3) centrifugal<p> Which of the following pumps are self-priming, and can deal with liquid from a level below the pump()<br /> (1) ejector<br /> (2) screw<br /> (3) centrifugal</p>
A、A.(1)only
B、B.(1)and(2)
C、C.(1),(2)and(3)
D、D.(2)and(3)