A schematic of the solution is shown below. The information from the question is given in black. Deductions directly from this information are given in red. Points that provide potential key information are shown by green arrows. The "key information" that allows the correct solution to be found is probably that A is the secondary alcohol  2-butanol (based on formula, spectral data and reaction data). The important knowledge required to solve the problem is a strong knowledge of the reactions involved, definitions of terms and counting types of C.....