An organic compound (A),`C_(8)H_(4)O_(3)` in dry benzene in the presence of anhydrous `AlCl_(3)` gives ,compound (B). The compound (B) on treatement with `PCl_(5)` followed by reaction with `H_(2)//Pd-BaSO_(4)` gives compound C, which on reaction with hydrazine gives a cyclised compound (D) of formula `C_(14)H_(10)N_(2)`. Identify (A),(B),(C ) and (D). Explain the formation of (D) and (C ).
