A mixture of acetic acid and sodium acetate acts as buffer solution around pH P and a mixture of ammonium chloride and ammonium hydroxide acts as a buffer around pH Q . P and Q respectively are

• A

  9.25 and 4.75

• B

  4.75 and 9.25

• C

  8.74 and 3.87

• D

  3.87 and 8.74