what is the ka for 0.03M Solution of HClO4 for 1.90 PH value.

A) 7.2x10^-3
B) 8.27x10^-3
C) 8.27x10^-4
D) 6.27x10^-4


(I keep getting 5x10^-3 when I round all the values to 2 decimal places but it’s not in the options)