In basic medium the amount of `Ni^(2+)` in a solution can be estimated with the dimethylglyoxime reagent. The correct statement(s) about the reaction and the product is (are)

Options

A. in ammoniacal solution, `Ni^(2+)`salts give cherry-reaction precipitate of nickel (II) dimethylglyoximate
B. two dimethylglyoximate units are bound to one `Ni^(2+)`.
C. in the complex two dimethylglyoximate units are hydrogen bonded to each other
D. each dimethylglyoximate unit forms a six-membered chelate ring with `Ni^(2+)`.