What Mass of Solid NaCH₃CO₂ (Molar Mass = 82 $\times$ 10² G

Multiple Choice

What mass of solid NaCH₃CO₂ (molar mass = 82.0 g/mol) should be added to 1.0 L of 0.50 M CH₃CO₂H to make a buffer with a pH of 7.21? (pK_a of CH₃CO₂H = 7.21)

A) 0.0 g
B) 1.9 g
C) 41 g
D) 71 g
E) 1.6 $\times$ 10² g