please explain why A is the answer

9.BufferAcontains22MMeachofformicacidandsodiumformateandbufferBhas0.4Meachofformicacidand2M sodium formate. Which solution will have the higher buffer capacity? (formic is a weak acid) (a.) Buffer A b. Buffer B c. Both buffer A and buffer B have equal buffer capacity. d. Buffer B when pH