You are asked to prepare a 500 mL 0.100M acetate buffer at pH 5.00 using only pure acetic acid (MW=60.05 g/mol, pKa=4.76).

Which of the following solutions should be added to the acetic acid to prepare the buffer?
a. 500 mL of 0.100M acetic acid
b. 500 mL of 0.100M sodium acetate
c. 250 mL of 0.200M acetic acid and 250 mL of 0.050M sodium acetate
d. 500 mL of distilled water