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Questions asked by users might not always be phrased in the clearest way.
The correct answer is B) 172.0 (+0.2). Here's how to determine the absolute uncertainty:
1. Calculate the sum: 12.34 + 178.1 - 18.493 = 172.0
2. Add the absolute uncertainties: 0.04 + 10.2 + 0.002 = 10.242
3. Round the absolute uncertainty to the same number of decimal places as the least precise measurement: The least precise measurement is 178.1 (with one decimal place), so the absolute uncertainty rounds to 0.2.
4. Express the final answer with the correct number of significant figures: Since the uncertainty is in the tenths place, the final answer should also be rounded to the tenths place. Therefore, the answer is 172.0 (+0.2).