67. The following figure is a Light-Emitting Diode (LED), and it will lit if
(A) Va<Vb
(B) Va=Vb
(C) Va>Vb
(D) never
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統計: A(5), B(5), C(41), D(0), E(0) #2929644
統計: A(5), B(5), C(41), D(0), E(0) #2929644