The complex that can show optical activity

cis-\( \left[\mathrm{Fe}\left(\mathrm{NH}_{3}\right)_{2}(\mathrm{CN})_{4}{ }\right] ^{-}\)

trans-\( \left[\mathrm{Cr}\left(\mathrm{Cl}_{2}\right)(\text { ox })_{2}\right]^{3-} \)

trans-\( \left[\mathrm{Fe}\left(\mathrm{NH}_{3}\right)_{2}(\mathrm{CN})_{4}{ }]^{-}\right. \)

cis- \( \left[\mathrm{CrCl}_{2}(\mathrm{ox})_{2}\right]^{2-}(\mathrm{ox}= \) oxalate \( ) \)