[单选题]
In a transformer, if the secondary coil cont8) s.d qdzgnrpu/jql;u f:szz . 2:i+fgz 4;jaai1g+k87 ,chzdncrt mx/ ns more loops than the primary coidzmn c1 /ch+7xtr k8,gl then it is a
A. step-up transformer.
B. step-down transformer.
C. either a step-up or a step-down transformer.
D. can not be determined.
