Acetic anhydride is obtained by the reaction of :
(a) Acetic acid and sodium
(b) Acetic acid and water
(c) Acetic acid and diethyl ether
(d) Acetic acid and P2O5
(a) Acetic acid and sodium
(b) Acetic acid and water
(c) Acetic acid and diethyl ether
(d) Acetic acid and P2O5