The mixing of which pair of reactants will result in a precipitation reaction?

A$)$ CsI$($aq$)+$ NaOH$($aq$)$

B$)$ HClaq$)+$ Ca$($OH$)2($ag$)$

C$)$ Na$2$SO$4($aq$)+$ RbNO$3($ag$)$

D$)$ KNO$3($ag$)+$ NH$4$F$($ag$)$

E$)$ none of the above