Ans: The answer is fumaryl chloride.
The reaction that is given in the question is Friedel craft acylation. This reaction is used to introduce an acyl group that is RCO- onto an aromatic ring with the help of acid halide that is in the presence of Lewis acid catalyst. The equation for Friedel-Crafts acylation is:
Ar-H + RCOX + Lewis Acid → Ar-COR + HX
The reactions which cannot be applied to prepare an alkene by elimination, are
Choose the correct answer from the options given below: