Which single duty did Parliament keep in 1770 when it repealed the Townshend duties?

1. Townshend had laid duties on paper, glass, lead and tea exported from Britain to the colonies. 2. Colonial boycotts and violence in Boston made those duties costly to collect. 3. In 1770 Parliament made a strategic retreat and repealed all of them except the duty on tea. 4. George III wanted one tax kept so that the right to tax was kept with it. 5. Most colonists read the repeal as a redress of grievances and let the campaign drop. _Source: An Outline of American History (U.S. Information Agency, 1990, public domain), section TAX DISPUTE ABATES_