Coordination Compounds

Homoleptic complexes among the following are

(A) \(\mathrm{K}_3\left[\mathrm{Al}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]\)

(B) \(\left[\mathrm{CoCl}_2(\mathrm{en})_2\right]^{+}\)

(C) \(\mathrm{K}_2\left[\mathrm{Zn}(\mathrm{OH})_4\right]\)