The correct option is C Chloroauric acid
Aqua regia is the mixture of concentrated hydrochloric acid and concentrated nitric acid in `1:3` ratio.
Gold dissolves in aqua-regia as,
`6HCl+3HNO_3 \rightarrow 2NO+4H_2O+3Cl_2`
2Au+11HCl+3HNO3→2HAuCl4(chloroauric acid)+3NOCl+6H2O
Au+4HCl+HNO3→H[AuCl4](chloroauric acid)+2H2O+NO