Explanation:
The correct answer is option C) He was shy.

Reasoning:
The reason the other boy did not join Ranji in swimming was that he was shy. Shyness is a personality trait characterized by feelings of apprehension, discomfort, or awkwardness in social situations. Shy individuals often feel self-conscious and may avoid participating in activities that require them to interact with others or draw attention to themselves.

Shyness and swimming:
Swimming is a social activity that often takes place in public spaces such as pools or beaches. It requires individuals to expose themselves in swimwear and interact with others. For someone who is shy, these factors can be overwhelming and cause anxiety.

Shyness and fear of judgment:
Shy individuals may have a fear of being judged or negatively evaluated by others. They may worry about their appearance, swimming abilities, or making mistakes in front of others. These fears can prevent them from participating in activities like swimming, where they feel exposed and vulnerable.

Lack of self-confidence:
Shyness is often associated with low self-confidence. Shy individuals may doubt their abilities and feel unsure of themselves. They may worry about not being able to keep up with others or feeling embarrassed if they make a mistake while swimming. This lack of self-confidence can hold them back from joining activities like swimming.

Preference for solitude:
Some individuals, including shy people, may have a preference for solitude and enjoy activities that can be done alone. While swimming can be a solitary activity, it is often associated with socializing and being part of a group. The other boy may have preferred to swim alone to avoid social interactions and enjoy his own company.

Conclusion:
In conclusion, the other boy did not join Ranji in swimming because he was shy. Shyness can cause individuals to feel anxious and self-conscious in social situations, leading them to avoid activities that require interaction with others.