Final answer:
A stroke patient with impulsivity likely had a lesion in the right hemisphere.
Step-by-step explanation:
When a stroke patient presents with impulsivity, it is likely that they have a lesion in the right hemisphere. The right hemisphere of the brain controls the left side of the body, and damage to this hemisphere can result in behavioral changes, including impulsivity. Impulsivity can manifest as impulsive actions, such as eating food without paying for it, as described in the scenario.