To Calculate the PH of a System That Has 0

To calculate the pH of a system that has 0.010 M HCl, 0.10 M HF, and 0.10 M HCOOH:

A) Consider only the HCl.
B) Look up the K _a values for HF and HCOOH and use the stronger to calculate the pH.
C) Add up the concentrations of HF and HCOOH and use the average value of K _a.
D) Titrate with NaOH in the lab.
E) Calculate K _b for all the species and rank them on a number line.