The Minimum Alternative Tax (MAT) is a tax built into the income tax system of India devised to help the government tackle non-payment of tax by certain corporations. It ensures that companies that claim tax deductions through exemptions, incentives, or rebates under the Income Tax Act pay a minimum amount of tax.

Option 1 states the year as 1991-92 and option 2 as 1992-93, these are incorrect as the concept of MAT was not introduced during these years.

Option 3 states the year 1995-96 which is not correct. MAT was initiated in the direct tax proposals for the annual budget for 1996-97, not in 1995-96.

Option 4 correctly identifies the year 1996-97. In this year, MAT was introduced for the first time in the Indian budget by the then finance minister. Therefore, the correct answer is 4, indicating the year 1996-97.