Which of the following aqueous solution/s will have a pH value...

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1. A0.01 M solution of benzoic acid $\left(\mathrm{K}_{\mathrm{a}}=6.6 \times 10^{-5}\right.$ at \left.25^{{}^{{}^{\circ}}} \mathrm{C}\right)
2. B0.02 mol benzoic acid and 0.05 mol sodium benzoate dissolved in appropriate amount of water to make a solution of 1L
3. CA mixture of 999 mL water and 1 mL 0.2 M HCl
4. D499 mL of 0.01 M NaOH and 501 mL of 0.01 M HCl mixed together