Among VO_2^+, MnO_4^- and Cr_2 O_7^2-, the spin-only magnetic moment value of the species with least oxidising ability is ____ BM (Nearest integer).…

Among $\displaystyle \mathrm{VO}_2^{+}, \mathrm{MnO}_4^{-}$and $\displaystyle \mathrm{Cr}_2 \mathrm{O}_7^{2-}$, the spin-only magnetic moment value of the species with least oxidising ability is $\displaystyle \_\_\_\_$ BM (Nearest integer). (Given atomic member $\displaystyle \mathrm{V}=23, \mathrm{Mn}=25, \mathrm{Cr}=24$ )