Why Cannot One Determine the Relative Acid Strengths of HClO₄

Why cannot one determine the relative acid strengths of HClO₄ and HNO₃ using aqueous solutions of these acids?

A) The acids are insufficiently soluble for the measurements.
B) A more basic solvent than H₂O must be used.
C) H₂O is too basic a solvent for the distinction to be made.
D) These oxidizing acids cause redox reactions to occur.
E) Actually,the acid strengths can be determined using aqueous solutions.