A compound A having the composition $\mathrm{FeC_9H_8O_3}$ shows one signal at 2.5 ppm and another one around 5.0 ppm in its ${}^{1}\mathrm{H}$ NMR spectrum. The IR spectrum of this compound shows two bands around $1680\,\mathrm{cm^{-1}}$. The compound follows the 18 electron rule of the following statements for A, the correct one is/are(A) It has $\eta^{5}\text{-}\mathrm{Cp}$ group.(B) It has a terminal CO ligand.(C) It has a $\mathrm{CH_3}$ ligand(D) It has Fe-H bond.