Which of the following molecules gives 'Glyoxal' as one of the product on reductive ozonolysis?

The product of which of the following reactions forms a reddish brown precipitate when subjected to Fehling's test? 

Compound P and R upon ozonolysis produce Q and S, respectively. The molecular formula of Q and S is ${\mathrm{C}}_8{\mathrm{H}}_8\mathrm{O}$ . Q undergoes Cannizzaro reaction but not haloform reaction, whereas S undergoes haloform reaction but not Cannizzaro reaction.

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Identify the major product in the following reaction

$\mathrm{A}$ is 

In the following reaction-

The major product $\mathrm{X}$ is-