问题：

[单选] One method of determining crankshaft misalignment is by（）

A . laying a straight edge across the crank webs at the crankpin and measuring the distance to the crankpin in two places
B . measuring the crank drop on either side of each crank throw while the crankshaft is slowly rotated through one revolution
C . rotating the crankshaft through one revolution, pausing each 90oof rotation to measure bearing clearances, top and bottom
D . taking micrometer reading between the crank cheeks opposite the crankpin every 90°of crank angle rotatio