Please answer this multi-part question. For part a, please write the steps that lead to the correct compound. For instance, if it is aliphatic/acyclic, contains double bond, etc.

a. The 'H NMR spectrum of a concentrated solution of an organic compound having the molecular formula CHO, showed three singlets: 82.1 (3H), 84.5 (2H), and 84.9 (1H). Suggest a structure for the compound.

b. How can the 'H NMR signal for the alkyne C- H be distinguished from the O- H signal for propargyl alcohol (HC=CCH OH)?