Final answer:
One cause of colonial unhappiness with British rule in 1776 was D. unfair taxation policies imposed by the British government.
Step-by-step explanation:
One cause of colonial unhappiness with British rule in 1776 was unfair taxation policies. The British government imposed a series of acts and taxes on the American colonies, such as the Stamp Act and the Townshend Acts, that were designed to raise revenue and regulate trade. The colonists strongly opposed these taxes because they believed that they should only be taxed by a legislature that they themselves elected.
The colonists argued that since they had no representation in the British Parliament, they should not be subjected to taxes imposed by that body. Additionally, they believed that internal taxes, which directly affected their everyday lives, were particularly unjust.