# In salt bridge the electrolyte used should be

$\begin{array}{1 1}(A)\;Reactive&(B)\;Inert\\(C)\;Neutral&(D)\;None\end{array}$

In salt bridge the electrolyte used should be inert
Salt bridge is U – shaped glass tube filled with a gelly like substance, agar – agar (plant gel) mixed with an electrolyte like $KCl, KNO_3, NH_4NO_3$ etc.
The electrolytes of the two half-cells should be inert and should not react chemically with each other.
Hence (B) is the correct answer.
edited Nov 22, 2017