溴酸钾法测定苯酚的反应如下：BrO3- +5Br- +6H+=3BR3+3H2O，C6H5OH+3Br2=C6H2Br3OH+3

溴酸钾法测定苯酚的反应如下：BrO3- +5Br- +6H+=3BR3+3H2O，C6H5OH+3Br2=C6H2Br3OH+3HBr，BR2+2I-=I2+2Br-，I2+2S2O3 2-=S4O6 2-,在此测定中，Na2S2O3与苯酚的物质的量之比为( )

A.0.25069444444444

B.0.12569444444444

C.0.084027777777778

D.0.042361111111111

正确答案是A