During check on top clearance in main bearings, turn the crankthrow for the relevant cylinder unit to （） and stop the lube oil circulating pump.

A.the piston cooling oil return pipes
B.the main and crankpin bearings
C.thrust and intermediate bearings
D.stern tube and thrust bearings

A.the upward stroke
B.the downward stroke
C.the power stroke
D.the suction stroke

A.clockwise
B.anticlockwise
C.crosswise
D.vertically