In this analogy question, complete the pair that shows a part and its whole: Head : Human Body :: ?

Introduction / Context:
This analogy question is based on the part and whole relationship. The head is a part of the human body, and you must choose the option that similarly relates a geometric part to its whole figure. Recognizing these structural relationships is a common task in verbal and non verbal reasoning sections.

Given Data / Assumptions:
- The first pair is Head and Human Body.
- Head is a part or component of the entire human body.
- The answer choices pair various geometric shapes with a circle: Arc : Circle, Cube : Circle, Square : Circle, and Triangle : Circle.
- We assume standard geometric definitions, where an arc is part of a circle and the other shapes are independent figures.

Concept / Approach:
The essential concept is that the first word in each pair should denote a part that naturally belongs to the whole indicated by the second word. A head is not a separate full body on its own; it is one component of the human body. Similarly, an arc is a continuous portion of the circumference of a circle and cannot exist as that specific curve without the circle. Therefore the pair Arc : Circle best mirrors the relationship in Head : Human Body.

Step-by-Step Solution:
Step 1: Recognize that Head is a part of the Human Body.Step 2: Now examine each option to see which first item is a part of a Circle in the same way.Step 3: An Arc is a portion of the circumference of a Circle, so it is directly a part of a circle.Step 4: A Cube is an independent three dimensional solid and not a part of a Circle.Step 5: A Square is a two dimensional shape with four equal sides, not a part of a Circle.Step 6: A Triangle is another separate two dimensional shape and not inherently a part of a Circle.Step 7: Therefore only Arc : Circle correctly reflects the part whole relationship found in Head : Human Body.

Verification / Alternative check:
Restate the pairs in descriptive sentences. A head is a part of the human body. An arc is a part of a circle. By contrast, a cube is not a part of a circle, a square is not a part of a circle, and a triangle is not a part of a circle. This sentence based check confirms that only Arc fits the same type of relationship with Circle as Head does with Human Body.

Why Other Options Are Wrong:
- Cube : Circle: A cube is a solid figure and a circle is a plane figure; one is not a part of the other.
- Square : Circle: A square is a separate geometric figure, not a component of a circle.
- Triangle : Circle: A triangle is also a complete figure by itself and does not naturally form a part whole relationship with a circle in the way an arc does.

Common Pitfalls:
Some learners may be distracted by similarities between the names of shapes or by thinking about diagrams where multiple shapes appear together. However, the question focuses specifically on the structural relationship of part to whole, not on co existence in a picture. To solve such questions effectively, always ask whether the first item can be described as an essential or clear part of the second item, rather than a separate figure.

Final Answer:
Because Head is a part of the Human Body and an Arc is a part of a Circle, the correct completion of the analogy is Arc : Circle.