After preparing the probability distribution of cost outcome for a project, the estimate, with a 15% probability of being exceeded, is approximately one standard deviation ______ .

A) below the mean
B) above the median
C) above the mean
D) above the median

树脂颗粒的大小，对水处理的工艺过程有较大的影响。颗粒大，交换速度（）；颗粒小，水通过树脂层的压力损失（）。