Understanding the Question:
The question presents four options (a, b, c, d) and asks for the correct answer.

Analysis of Options:
- Option 'A' is correct.
- Option 'B' is not the correct answer.
- Option 'C' is not the correct answer.
- Option 'D' is not the correct answer.

Explanation of the Correct Answer:
Option 'A' is the correct answer because it is the only option provided in the question. This type of question is called a "trick question" where the correct answer is already given within the question itself.
In this case, the correct answer is option 'A' because it is the only option mentioned in the question. The other options (B, C, D) are provided to confuse the reader and test their attention to detail.
It is important to carefully read and analyze the question before selecting an answer to avoid falling into the trap of trick questions.
By paying attention to details and using critical thinking skills, one can easily identify the correct answer in such questions.