`Hg(NO_(3))_(2) overset(Delta) to W + X + O_(2)`
`X + H_(2)O rarr HNO_(2) + HNO_(3)`
`W + HNO_(3) rarr Y + NO + H_(2)O`
`Y + Na_(2)S_(2)O_(3) ("excess") rarr 2 + NaNO_(3)`
A. `{:("W"," X"," Y"," Z"),(Hg,N_(2)O,Hg(NO_(3))._(2),Na_(2)[Hg(S_(2)O_(3))_(2)]):}`
B. `{:("W"," X"," Y"," Z"),(Hg,NO,Hg(NO_(3))._(2),Na[Hg(S_(2)O_(3))_(2)]):}`
C. `{:("W"," X"," Y"," Z"),(Hg,NO_(2),Hg(NO_(3))._(2),Na_(2)[Hg(S_(2)O_(3))_(2)]):}`
D. `{:("W"," X"," Y"," Z"),(Hg,N_(2)O_(3),Hg(NO_(3))._(2),Na_(3)[Hg(S_(2)O_(3))_(2)]):}`