Which of the following will be the advantage of a centrifugal pump as compared with a reciprocating pump?（）
(1) Its discharge is continuous
(2) It has no internal valves
(3) Upon accidental closing of discharge valve, excessive pressure will not build up

A.（1），（2）
B.（2），（3）
C.（1），（2），（3）
D.（2）only