By which pf the following reactions can methylcyanide be prepared?
A. `CH_(3)Br underset(DMF)overset("KCN")rarr `
B. `CH_(3)NH_(2)+CHCl_(3) overset("KOH") rarr `
C. `CH_(3)-CH =N-OH underset(triangle) overset(P_(2) O_(5))rarr `
D. `CH_(3)-overset(O)overset(||)(C)-NH_(2) overset(P_(4)O_(10))underset(triangle)rarr`
