The Enzyme Fumarase Has a PH Optimum of About 7

The enzyme fumarase has a pH optimum of about 7.6. What would be the buffer of choice to study this enzyme?

A) lactic acid (K_a = 1.38 × 10−⁴, pK_a = 3.86)
B) bicarbonate (K_a = 6.3 × 10−¹¹, pK_a = 10.24)
C) acetic acid (K_a = 1.74 × 10−⁵, pK_a = 4.76)
D) succinate (K_a = 2.34 × 10−⁶, pK_a = 5.63)
E) tris-hydroxymethyl aminomethane (K_a = 8.32 × 10−⁹, pK_a = 8.07)