Introduction:
In India, the currency notes are issued by the Reserve Bank of India (RBI) and have certain distinct features, including the signature of the authority responsible for issuing the currency. The 100/- Rupee note, in particular, is signed by a specific authority. Let's explore the options and understand why the correct answer is option 'C' - RBI Governor.

Explanation:
To understand why the 100/- Rupee note is signed by the RBI Governor, let's consider each option:

a) Prime Minister:
The Prime Minister of India is the head of the government and is responsible for policy-making and governance. However, the Prime Minister does not have the authority to sign currency notes. The Prime Minister's signature does not appear on any denomination of Indian currency.

b) Finance Minister:
The Finance Minister is responsible for managing the country's finances, including revenue generation, budgeting, and fiscal policies. Similar to the Prime Minister, the Finance Minister does not have the authority to sign currency notes. The Finance Minister's signature is also not present on any denomination of Indian currency.

c) RBI Governor:
The Reserve Bank of India (RBI) is the central banking institution of India and has the authority to issue currency notes. The RBI Governor is the highest-ranking official of the Reserve Bank and is responsible for its overall functioning. The RBI Governor's signature appears on all currency notes, including the 100/- Rupee note.

d) None of the above:
This option is incorrect since the 100/- Rupee note is indeed signed by a specific authority, which is the RBI Governor.

Conclusion:
The 100/- Rupee note in India is signed by the RBI Governor. It is important to understand the roles and responsibilities of different authorities to have a comprehensive understanding of the functioning of financial systems.