Explanation:

- The Value-Added Tax (VAT) was introduced in India to streamline the taxation system and replace the pre-existing general sales tax.

- Option 1, 2005: The Government of India implemented VAT in April 2005. It aimed at bringing uniformity in the tax structure across states and improved compliance.

- Option 2, 2011: In 2011, while there were discussions and modifications around indirect taxes, VAT was already in place since 2005.

- Option 3, 2013: No major introduction of VAT happened in 2013, as it had been established in 2005.

- Option 4, 2007: By 2007, VAT had been functioning for two years already.

The correct answer is Option 1, 2005.