Option 4 is correct, i.e. If the question arises whether a bill is a money bill or not, the decision of the leader of the opposition shall be final.
Lok Sabha Speaker certifies the bill as a money bill before sending it to the upper house, and the decision of the Speaker is binding on both the Houses.He/she represents the full authority of the House and decides whether a bill is a money bill or not.
A money bill or supply bill is a bill that solely concerns taxation or government spending.
The Speaker appoints the Secretary-General of the Lok Sabha.
The Lok Sabha speaker is the presiding officer of the Lok Sabha.
The Speaker ranks sixth in the hierarchy of State government of India, equivalent with the Chief Justice.
Money bills are defined in Article 110 of the Indian Constitution. Special procedure regarding Money Bills is contained in Article 109.
The Upper House of the Parliament i.e. the Rajya Sabha does not have the right to amend the Money bills. It can only recommend amendments.
The Annual Financial (Budget) bills and the Appropriation bills are termed as the Money bills.