下列生物性状的差异是因变异直接导致的是[ ]

A．家鸽和大雁羽毛的颜色不同        

B．双亲正常，孩子中有人患白化病  

C．家蚕的幼体和成体有明显差异      

D．蝗虫的体色夏天是绿色，秋天是黄色

—How come you are always staring at me this morning?

—You look stupid! The way you wear is________ annoys me most.

A．which

B．where

C．how

D．what