Beauty is not external, if a person does his work with utmost sincerity then it would be regarded as beautiful. That's why people become beautiful by working in fields. 

Introduction:
Beauty is a subjective concept that varies from person to person. While physical appearance is often associated with beauty, it is important to note that beauty is not solely determined by external factors. It is a combination of various qualities, including inner qualities such as kindness, confidence, and intelligence, that contribute to a person's overall beauty. In this context, option 'A' - working in fields - can be understood as a metaphor for personal growth and development, which plays a significant role in enhancing one's beauty.

Explanation:
Physical beauty can be enhanced through various means such as dressing up, using cosmetics, and maintaining a healthy lifestyle. However, true beauty goes beyond physical appearance and encompasses qualities that are developed through personal experiences and growth. Working in fields, metaphorically representing personal growth, can contribute to one's overall beauty in the following ways:

1. Building Confidence:
Working in fields allows individuals to develop skills, gain knowledge, and achieve personal milestones. This process builds confidence as individuals become more proficient in their work and develop a sense of accomplishment. Confidence is an attractive quality that radiates from within and enhances a person's overall beauty.

2. Cultivating Compassion:
Engaging in work that involves helping others or contributing to society fosters compassion. Compassion is a beautiful trait that involves empathy, kindness, and a genuine concern for others. When individuals actively engage in helping others, they develop a compassionate nature, which adds to their overall beauty.

3. Expanding Horizons:
Working in fields often requires individuals to step out of their comfort zones and explore new territories. This exposure to different environments, cultures, and perspectives broadens their horizons and contributes to personal growth. By embracing new experiences and learning from them, individuals become more open-minded, adaptable, and interesting, making them more beautiful in the eyes of others.

Conclusion:
While physical appearance is often associated with beauty, true beauty extends beyond external factors. Working in fields, representing personal growth and development, plays a significant role in enhancing one's beauty. By building confidence, cultivating compassion, and expanding horizons, individuals become more attractive not only in terms of physical appearance but also in terms of their inner qualities.