Cannizzaro or aldol condensation?
The aldol condensation needs $\alpha$-hydrogens next to the carbonyl group in order to proceed. Check out this reaction equation from the Wikipedia article:


One of these hydrogen atoms is removed to form the enolate. See this mechanism (also from the Wikipedia article). 



Now, look at the structure of p-methylbenzaldehyde. This molecule does not have any $\alpha$-enolizable hydrogen atoms. The $\alpha$-position is an $sp^2$-hybridized carbon atom in the aromatic ring. The aldol condensation is thus not possible.



We can also rule out the haloform reaction because there are no halogen compounds given. There are also no hydrolyzable functional groups (halides, ethers, esters, anhydrides, amides, nitriles, etc.).

The only remaining possibility is the Cannizzarro reaction, which requires a benzaldehyde derivative or other aldehyde lacking $\alpha$-enolizable hydrogen atoms.