Answer:
well it is to be a threat to the.......................
The letter signed by Samuel Adams caused very negative reactions in the British, which increased tensions between the British Parliament and Massachusetts, who not to give up what the letter said, led the British Empire to decide the occupation of the city of Boston by the British Army. This fact, in turn, and given the repressive forms of reaction of the British, was a fact that rushed and provoked the American Revolution. It should be noted that in the letter, it was expressed at the end that the settlers were still subjects of His Majesty and that only expressed with anguish their problems.
The WPB or War Production Board set the products that would be needed for war and they determined their pricing.
So I agree with you, the answer is A.
But I must admit I was a bit iffy between A and D but I'd still say that A is a better choice.
Hope this helped