The correct answer is D. no article.
The word "one" is a number, not a specific noun. Therefore, it does not require an article.
A and B are incorrect because they are indefinite articles. Indefinite articles are used to refer to a general or unspecified thing. In this case, Ram is giving a specific one rupee note, not a general or unspecified one rupee note.
C is incorrect because it is a definite article. Definite articles are used to refer to a specific or particular thing. In this case, Ram is giving a specific one rupee note, not a general or unspecified one rupee note.
Therefore, the correct answer is D. no article.
