in which of the following reactions propionic anhydride is not obtained?
A. `CH_(3)CH_(2)COOH overset(P_(2)O_(5)//Delta)rarr`
B. `CH_(3)CH_(2)COCl+CH_(3)CH_(2)COONa rarr`
C. `CH_(3)CH_(2)COOH+(CH_(3)CH_(2)CO)_(2)Ooverset(Delta)rarr`
D. `CH_(3)CH_(2)COOH+(C_(3)H_(7)CO)_(2)Ooverset(Delta)rarr`
