Among the following names of body parts, choose the one which is least like the others in the group.

Introduction / Context:
This question is from the classification subsection of logical reasoning. All the options are parts of the human body, but one of them belongs to a different functional category compared to the others. Recognising how each part functions in relation to movement and support helps identify the odd one out.

Given Data / Assumptions:

• Arm, a limb extending from the shoulder to the hand.
• Finger, one of the smaller movable parts at the end of the hand.
• Shoulder, the joint that connects the arm to the trunk.
• Foot, the lower extremity used for standing and walking.
• Hand, the terminal part of the arm used for grasping.
• We assume standard anatomical meanings of these terms.

Concept / Approach:
One useful way to classify these terms is to separate actual limbs or extremities from joints. Limbs and extremities such as arms, hands, fingers and feet are primarily used to perform actions like grasping or walking. A joint like the shoulder mainly functions as a connection and pivot point between the limb and the body. If most of the given words are limbs or parts of limbs and one is primarily a joint, that joint will be the odd one out.

Step-by-Step Solution:
Step 1: Arm is an upper limb. It is used for reaching, lifting, holding and many other actions, and it consists of bones, muscles and joints.Step 2: Finger is part of the hand, which itself is part of the upper limb. Fingers are used for grasping, touching and fine movements.Step 3: Foot is the terminal part of the lower limb. It supports the body weight and is used for standing, walking and running.Step 4: Hand is a distinct extremity at the end of the arm, used for grasping and manipulating objects.Step 5: Shoulder, in contrast, is a joint that connects the arm to the trunk of the body. It acts mainly as a pivot or attachment point rather than an extremity used directly for contact with the environment.Step 6: Thus, Arm, Finger, Foot and Hand are either limbs or terminal parts of limbs involved directly in performing actions, while Shoulder is primarily the joint where one of these limbs attaches to the body.Step 7: Therefore, Shoulder is functionally different and is the odd one out in the group.

Verification / Alternative check:
Another way to confirm the answer is to think of which parts actually touch and interact with external objects. You can touch and hold things with your hand and fingers, and you stand or walk using your feet. Your arm extends out and can itself come into contact with objects. The shoulder normally serves as an internal pivot and does not directly interact with objects in the same way. This supports the conclusion that Shoulder has a different functional role.

Why Other Options Are Wrong:
Arm, Finger, Foot and Hand are all actively used extremities or parts of extremities. They are not primarily joints; instead, they contain joints but also include bones, muscles and skin that directly interact with the outside world. Because of their similar role as active, external parts, they form a natural group and are not the odd one out.

Common Pitfalls:
Some learners may mistakenly think that Finger is the odd one out because it is smaller than the others or not an entire limb. However, size does not determine the classification here. The important distinction is between a joint (shoulder) and limb segments or extremities (arm, finger, foot, hand). Focusing on function and anatomical role instead of size leads to the correct answer.

Final Answer:
The body part which is least like the others is Shoulder.