The Cannizzaro reaction is a chemical reaction that involves the base-induced disproportionation of two molecules of a non-enolizable aldehyde to give a primary alcohol and a carboxylic acid (Wikipedia).
The haloform reaction requires a methyl ketone as the substrate.
Two compounds (P and R, respectively) in choice [A] give you 4-methylbenzaldehyde, $\ce{C8H8O}$ (Q; a non-enolizable aldehyde) and acetophenone, $\ce{C8H8O}$ (S; a methyl ketone) upon ozonolysis (byproduct from each compound is formaldehyde): 4-Methylbenzaldehyde can undergo Cannizzaro reaction but not haloform reaction (your given mechanism for bromform is unacceptable). Acetophenone, an enolizable ketone, easily undergoes haloform reaction but not Cannizzaro reaction (it is not an aldehyde).
Also, two compounds (P and R, respectively) in choice [B] give you 3-methylbenzaldehyde, $\ce{C8H8O}$ (Q; a non-enolizable aldehyde) and acetophenone, $\ce{C8H8O}$ (S; a methyl ketone) upon ozonolysis as well (byproducts from P and R here are acetaldehyde and acetone, respectively): 3-Methylbenzaldehyde can undergo Cannizzaro reaction (it is also a non-enolizable aldehyde) but not haloform reaction. Acetophenone, as pointed out earlier, undergoes haloform reaction but not Cannizzaro reaction (it is not an aldehyde).
Thus, both choices are correct.
Please also note that the compounds representing P and R in choices [C] and [D] will also give you a non-enolizable aldehyde and a methyl ketone upon ozonolysis. Each of these non-enolizable aldehyde and methyl ketone set shows the ideal reactivity towards Cannizzaro and haloform reactions as described earlier. However, they simply don't have the identical molecular formula as required.