A method for determining the structures of disubstituted benzene derivatives was proposed in 1874 by Wilhelm Korner of the University of Milan. Kdrner had in hand three dibromobenzenes, A, B, and C, with melting points of 89, 6.7, and - 6.5oC, respectively. He nitrated each isomer in turn and meticulously isolated all of the mononitro derivatives of each. Compound A gave one mononitro derivative; compound B gave two mononitro derivatives; and compound C gave three. These experiments gave him enough information to assign the structures of o-, m-, and p-dibromobenzene.
It is a testament to Korner's experimental skill that he could isolate all of the mononitration products. Of all the mononitration products that he isolated, which one(s) were formed in smallest amount? Explain.