Final answer:
The stroke most likely affected the precentral gyrus in the right frontal lobe, resulting in lack of sensitivity in the patient's right hand.
Step-by-step explanation:
The stroke most likely affected the precentral gyrus in the right frontal lobe. The precentral gyrus is responsible for motor control, specifically the control of voluntary movements in the opposite side of the body. In this case, the stroke affected the right precentral gyrus, leading to lack of sensitivity in the patient's right hand.