For H₂CO₃, K_a2 = 4

For H₂CO₃, K_a2 = 4.7 x 10^-11. Which of the following numbers is closest to the pH of a 0.200 M Na₂CO₃ solution? (Hint: Only the first step in the hydrolysis of the CO₃^2- ion need be considered in this calculation.)

A) 5.9 x 10^-3
B) 2.2
C) 2.48
D) 11.6
E) 11.8