The condition satisfied by the three routing coefficients of the muskingum method is

• A. \({{\rm{C}}_0} + {{\rm{C}}_1} + {{\rm{C}}_2} = 1\)
• B. \({{\rm{C}}_0} + {{\rm{C}}_1} + {{\rm{C}}_2} = 0\)
• C. \(\frac{{{{\rm{C}}_0}}}{{{{\rm{C}}_1}}} = \frac{{{{\rm{C}}_1}}}{{{{\rm{C}}_2}}}\)
• D. \({{\rm{C}}_0}{{\rm{C}}_1}{{\rm{C}}_2} = 1\)