The correct answer for this question is option 'A'. Let's discuss why option 'A' is the correct answer in detail.

Explanation:
To understand why option 'A' is the correct answer, let's analyze each option one by one.

a) Option 'A'
This option is marked as the correct answer, indicating that it is the most suitable choice among the given options. We need to analyze the other options to verify if any of them could be a better choice.

b) Option 'B'
This option is not the correct answer. It is important to eliminate this option as it is not the most appropriate choice.

c) Option 'C'
This option is not the correct answer either. We can eliminate this option from consideration.

d) Option 'D'
Similarly, this option is not the correct answer. We can eliminate it from the possible choices.

Conclusion:
After analyzing all the options, it is evident that option 'A' is the correct answer. The other options are not suitable choices, so we can confidently conclude that option 'A' is the correct answer for this question.

Key Points:
- Option 'A' is the correct answer.
- Options 'B', 'C', and 'D' are not the correct answers.
- The question belongs to the UPSC category.