单项选择题

用游标卡尺检测触杆Φ()柱面直径,小于Φ17.6mm时报废,划伤时可用细砂纸或油石打磨修理;用通针疏通触杆Φ1.5mm孔及Φ()孔。

A.18mm;10mm
B.19mm;4mm
C.18mm;5mm
D.18mm;4mm