Government revenue primarily consists of Tax Revenue and Non-Tax Revenue. Public debt is a source of capital receipt used for financing, not revenue in the strict sense. Deficit financing is a method of funding the fiscal deficit. The question asks about "importance in Government revenue," which points towards tax revenue components. Historically, and for a long period in India, Indirect Taxes (like excise duties, customs duties, sales tax/ VAT, and now GST) have contributed a larger share to the total tax revenue of the government (Centre and States combined) compared to Direct Taxes (like income tax and corporate tax). While the share of direct taxes has increased significantly over the years, especially for the Union Government, indirect taxes continue to be a highly important source of government revenue, particularly considering their broad base (affecting consumption) and contribution at both central (GST, Customs) and state levels (State GST, excise on petroleum, etc.). Given the options, and considering historical context and the overall tax structure (Centre + States), Indirect Tax remains a source of high relative importance in government revenue.