A and b I believe are correct
Answer
Davy Crockett
Explanation:
The legendary frontiersman and Tennessee congressman Davy Crockett opposed the Indian Removal Act, declaring that his decision would “not make me ashamed in the Day of Judgment.” he also wrote a letter criticizing the removal act.
Well, i think the answer would be : Standardized weight and measures
Standardized weight and measures first developed by the muslim merchants in Cairo. Before this standard, Length was measured by the length of one's body.
For example to measure silk, the usually used the term such as 1 arm length.
The thing is, many traders started to hire shorter people to measure this to gain profit , making exchange often became problematic
hope this helps