\begin{table}%t2
\caption{\label{tab:nullingvariants}Overview on nulling variants considered. }
%\centerline
 {\small \begin{tabular}[t]{cccc}
\hline \hline \noalign{\smallskip}
Variant & Foreground & Background & $0^{\rm th}$ Order weights\\
\hline
(A) & bin center & lower boundary & $1-\chi(\hat{z}_i)/\chi(z_j)$\\
(B) & bin center & bin center & $1-\chi(\hat{z}_i)/\chi(z_j)$\\
(C) & median redshift & bin center & $g^{(j)}\br{\chi(\hat{z}_i)}$\\
\hline
\end{tabular}}
\medskip
The variants differ by the redshifts assigned to the foreground and background photometric redshift bins, and by the form of the zeroth-order weight function.
\end{table}