The contribution of taxpayers to primary education is in the form of

Taxpayers contribute to primary education mainly through the educational cess levied on taxes.

Income tax (A) is a general tax, not earmarked specifically for primary education.

Tuition fee (B) is paid by parents to schools, not a taxpayer contribution.

Paying for individual tuition (C) is a private household expense, not public funding.

A cess is a tax levied for a specific purpose, here funding education.

The education cess was introduced in 2004 to fund universal elementary education.