In manning‚Äö√Ñ√∂‚àö√ë‚àö¬•s formula, V = 1/n‚Äö√†√∂‚àö‚â•m2/3‚Äö√†√∂‚àö‚â•i1/2. N stands for __________?#

In manning‚Äö√Ñ√∂‚àö√ë‚àö¬•s formula, V = 1/n

1.	In manning‚Äö√Ñ√∂‚àö√ë‚àö¬•s formula, V = 1/n‚Äö√†√∂‚àö‚â•m²/3‚Äö√†√∂‚àö‚â•i^1/2. N stands for __________?#
A.	Coefficient of viscosity
B.	Coefficient of rugosity
C.	Coefficient of runoff
D.	Coefficient of friction
Answer» C. Coefficient of runoff