某管流流动为层流,若管道的长度不变,通过的流量不变,欲使摩擦阻力损失减少到原来的四分之一,管路直径需变为原来的( )倍。

A、<img src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/examination/imgUplod/1526097374004eb2ade1054d34e40b6fe93a6258ca928.png" alt="上传图片"><br>

B、<img src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/examination/imgUplod/1526097382177e920d37b0a6a4ebda5ea8128abae876d.png" alt="上传图片"><br>

C、<img src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/examination/imgUplod/1526097390277355f23f1264a4ae2b38ead843927c37e.png" alt="上传图片"><br>

D、2