Amongst $\;LiCl , RbCl , BeCl_{2}\;$ and $\;MgCl_{2}\;$ the compounds with the greatest and the least ionic character , respectively are :

Question

$(a)\;LiCl\;and\;RbCl\qquad(b)\;RbCl\;and\;BeCl_{2}\qquad(c)\;MgCl_{2}\;and\;BeCl_{2}\qquad(d)\;RbCl\;and\;MgCl_{2}$