In Which Solution Is the [H₃O⁺] Less Than 0

Multiple Choice

In which solution is the [H₃O⁺] less than 0.250 M?

A) 0.250 M HC₂H₃O₂ (aq)
B) 0.250 M HF (aq)
C) 0.250 M HCO₂ (aq)
D) all of these
E) none of these