You run a chemistry lab and have found that your new lab assistant has labelled four different compounds (A,B,C,and D) with the formula C4H6. You know these compounds are isomers, but they are also chemically different. All four unknowns decolourize Br2 in CH2CL2. A and B for butane and each absorb 2 moles of H2. Compound B reacts with NaNH2 and then CH3Br to form a five carbon compound. The other compounds (A,C, and D) do not react. Treatment of compounds C with KMnO4 affords compound E, while compound D forms compound F under the same conditions (Structures are attached). Suggest suitable labels for compounds A,B,C,and D.