The main factor that made the taxes after the French and Indian War different from those imposed before the war, and that consequently sparked colonial protests, was the colonists had no voice in Parliament.
After the war, the British government sought to recover the debts incurred during the conflict and raise revenue to pay for the protection of the colonies. They imposed several new taxes, such as the Stamp Act and the Townshend Acts, which were viewed by the colonists as unjust. The key issue was that the colonists had no representation in the British Parliament and believed it was unfair to be taxed without their consent. This led to the rallying cry of "no taxation without representation" and fueled significant protests and resistance movements throughout the colonies.
While the other options highlight grievances that were indeed present (such as the high cost of taxes and the perception that the tax revenues did not benefit the colonists), the core issue that ignited widespread protest was primarily the lack of representation in the decision-making process regarding taxation.