The reaction depicted in the image appears to undergo an aldol condensation. Let's break down the steps involved:

1. Reagents and Reaction Conditions:

   • Cyclohexanone (a ketone) is reacted with benzaldehyde (an aldehyde).
   • NaCN is used as a catalyst in DMF (dimethylformamide).

2. Mechanism: This is a typical crossed aldol reaction where:

   • Cyclohexanone forms an enolate ion in the presence of NaCN.
   • The enolate ion attacks the carbonyl carbon of benzaldehyde.
   • This nucleophilic addition forms a beta-hydroxy ketone.
   • Under the reaction conditions, dehydration occurs, resulting in the formation of an α,β-unsaturated ketone.

3. Product Formation:

   • The major product [X] is a conjugated system where the double bond forms between the alpha and beta carbons relative to the ketone.

Conclusion: Based on the steps above, the major product [X] is formed through aldol condensation and dehydration. The structure of the major product is:

This structure represents the α,β-unsaturated ketone derived from cyclohexanone and benzaldehyde.