A Buffer Solution Contains Carbonic Acid (H₂CO₃) and Sodium Bicarbonate

A buffer solution contains carbonic acid (H₂CO₃) and sodium bicarbonate (NaHCO₃) , each at a concentration of 0.100 M.The relevant equilibrium is shown below.What is the pH of this buffer solution? H₂CO₃(aq) + H₂O(l) H₃O⁺(aq) + HCO₃−(aq) K_a = 4.5 × 10⁻⁷

A) 4.50
B) 7.00
C) 6.35
D) 7.65
E) 2.16