When 9.5 g of lithium stearate (LiC₁₈H₃₅O₂, MW = 290.47 g/mol) is dissolved in 550 g benzene, the resulting solution freezes at 0.30 °C lower than pure benzene (FP = 5.5 °C). Calculate the value of Kf (freezing point constant) for benzene.

• A. K_f = 2.8 °C•kg/mol
• B. K_f = 4.6 °C•kg/mol
• C. K_f = 5.4 °C•kg/mol
• D. K_f = 5.0 °C•kg/mol