The correct answer is option 4.

Option 1 states that domestic companies had to pay tax surcharge at the rate of 15 percent. This statement is incorrect because during the year 2000-01, the tax surcharge for domestic companies was actually 10 percent and not 15 percent.

Option 2 states that a tax rebate of Rs. 10,000 had been introduced for women taxpayers below 65 years of age. This statement is not relevant to the taxes in India during the year 2000-01, as no such tax rebate was introduced for women taxpayers during that time.

Option 3 states that the tax rebate for senior citizens had been increased from Rs. 10,000 to Rs. 30,000. This statement is also incorrect because there was no increase in the tax rebate for senior citizens during the year 2000-01.

Option 4 states that non-agricultural income of farmhouses was made taxable. This statement is correct, as during the year 2000-01, the non-agricultural income of farmhouses was indeed made taxable. This means that farmhouses had to pay taxes on any income generated from non-agricultural activities.

In conclusion, option 4 is the correct statement about taxes