Ranking Strength of Acids

In a laboratory experiment, a chemist is investigating the ability of various acids to donate protons in aqueous solution. The acids tested include hydrochloric acid (HCl), acetic acid (CH₃COOH), sulfuric acid (H₂SO₄), and phosphoric acid (H₃PO₄). The chemist measures the pH of each solution and determines their dissociation constants (K_a). HCl is known to completely dissociate in water, whereas the others exhibit partial dissociation. If the pH of a solution of HCl is found to be 1.0, what can be concluded about the strength of these acids?

Based on their abilities to donate protons and the impact on pH, which one of the following statements correctly ranks these acids from the strongest to the weakest?