[单选题]
At which position in the nephrook .5e9 aof2k (9;zixnxnnqu h,sb- k)n would yon/ 7ej5q1k c yhi56rpou expect the solute concentration of the filtrate to be between 200% and 300% that of the normal blood solute concentration and for water, but not sodium, to be drawn out of the filtrate into thknq rihcye7/15pjo 56 e medulla?