She worked hard everything would be ready in time.
A:such that
B:so that
C:so what
D:such what
如图所示,在平面直角坐标系xOy中,点B,C分别在x轴和y轴非负半轴上,点A在第一象限,且∠BAC=90°,AB=AC=4,那么O,A两点间距离的( )