跳汰机给煤量与（）及跳汰机结构特征、跳汰机床层的工作性质有关，在选煤操作中，应尽力保持给煤量均衡、稳定。

This new model of car is so expensive that it is _______ the reach of those with average incomes.   [ ]

A. over      

B. within    

C. beyond      

D. below