Correct Answer - C
`Zn^(2) +4NH_(3) hArr [Zn(NH_(3))_(4)]^(2+)`
`K_(f ) =([Zn(NH_(3))_(4)]^(2+))/([Zn^(2+)][NH_(3)]^(4)=3xx10^(9)`
`therefore ([Zn(NH_(3))_(4)]^(2+))/([Zn^(2+)]=[NH_(3)]^(4)xx3 xx10^(9)`
` = 10^(4) xx3xx10^(9) = 3xx10^(13)`
`therefore ([ Zn^(2+)])/([Zn(NH)_(3)_(4)]^(2+))=3.3xx10^(-14)`