Which of the following ions form most stable complex compound

The magnitude of stability constants for some divalent metal ions of the first transition series with oxygen or nitrogen order  ligands increases in the order

${\mathrm{Mn}}^{2+}<{\mathrm{Fe}}^{2+}<{\mathrm{Co}}^{2+}<{\mathrm{Ni}}^{2+}<{\mathrm{Cu}}^{2+}<{\mathrm{Zn}}^{2+}$