Which key concept did charles i agree to in the petition of right (1628)?

no parliament
no hereditary monarchy
no taxation without representation
no state religion

The answer is option 3: No taxation without representation.

The Petition of Right (1628) was a petition from the English Parliament to King Charles I, to put a halt on the his abuses of power that included imposing taxes without the Parliament's consent, imprisonments without trial when people resisted to pay the taxes, among others.

The Petition of Right demanded that no taxation would be imposed without the consent of Parliament ("No taxation without representation"), that no one would be imprisonment without a just cause, no subject had to provide living quarters to soldiers and no martial law should be enacted in peacetime.

a. competition with other nations.

answer; taking up arms to defend the nation;