A 33.7 mL solution of 0.861 mol L⁻¹ HCOOH is titrated using 0.14 mol L⁻¹ NaOH. What volume of NaOH (in mL) is needed to reach the equivalence point in this experiment?
a) 5.04 mL
b) 7.28 mL
c) 12.14 mL
d) 16.32 mL