theories approximate the truth is the day-to-day business of science.

A. Determining how closely B, How closely to determine

C,How one determine close D.One is close to determine

答案是A，但是我觉得B这种结构也对，请教高手指点。

结构上看，determine和approximate还有is都是动词，三者之间至少要有2个连词或者关系代词或者关系副词，而全句只有一个how，错。

语义上也无法理解。