[单选] Which item is correct about GCSD？ 下面关于GCSD哪个描述是正确的a． We can calculate the time by using different process， such as for cut wire we can use automatic cut by komax or manual cut + manual crimping 我们可以根据我们的实际情况来算工时 ，比如切线我们可以用Komax自动压接或手工切线+手工压接"b． The stardard time in GCSD is estimated by experience GCSD里的 时间是根据经验值定义的 "c． The standard process time is only running time of the operation 标准的过程时间仅仅是操作的运行时间"d． The standard time include preparation time．标准时间包括准备时间 "