The largest source of tax revenue of the Union (Central) Government of India in 2013-14, among the following, was

Sales tax is a State levy and export duty yields very little. Per the Union Budget 2013-14 receipt documents, taxes on income (about Rs 2.48 lakh crore budgeted) exceeded Union excise duties (about Rs 1.98 lakh crore budgeted, revised to about Rs 1.80 lakh crore), so income tax was the largest among the options.