Explanation:

- Option 1: Head : Brain

- Involves an organ located inside the head.

- Represents part-whole relationship.

- Option 2: Hand : Wrist

- The wrist is a part of the hand region.

- Represents a part-whole relationship but both are part of the same limb.

- Option 3: Arm : Shoulder

- The shoulder connects the arm to the body.

- Represents a part-whole relationship within the upper body limb connection.

- Option 4: Feet : Ankle

- The ankle connects the foot to the leg.

- Represents a part-whole relationship similar to Option 2 and 3.

Option 1: Head : Brain is the odd pair because it represents a different relationship than the others, moving from external to internal rather than segment to segment or connection.