The question asks for the tax that the Standing Committee of State Finance Ministers advised to be uniform rates across the states in January 2000.

Option 1 - Value-added tax: This is a type of consumption tax that is placed on a product whenever a value is added at a stage of production and at final sale. The committee didn`t recommend uniform rates for this.

Option 2 - Sales tax: This is a tax on sales or on the receipts from sales. The correct answer is sales tax, signaling that the Standing Committee suggested having a uniform sales tax rate across all states.

Option 3 - Stamp duty and registration fees: These are taxes that apply to documents and transactions, respectively. The committee didn`t propose standardized rates for these.

Option 4 - Agricultural income-tax: This is a tax on income derived from agriculture. The committee also didn`t suggest uniform rates for this tax.

So, the finance ministers recommended uniformity for sales tax (Option 2), not value-added tax (Option 1), stamp duty and registration fees (Option 3), or agricultural income tax (Option 4).