Hydrosulfuric acid is a diprotic acid, for which Ka1 = 5.7 × 10⁻8 andKa2 = 1 × 10⁻19. Determine the concentration of sulfide ion in a 0.10 M hydrosulfuric solution.
What do I do with Ka2 ? I set up the RICE table and solved for the HS- ion, after that I set another RICE table up to get the S2- ion completely alone. Please explain the process as best as you can! Thanks!

A) 7.5 × 10⁻5 M
B) 1 × 10⁻19 M
C) 5.7 × 10⁻9 M
D) 0.10 M
E) 1 × 10⁻20 M