The best example of an adverb phrase is B. Mr. Bruns had been teaching for 35 years.
This is an adverb phrase, because the phrase "for 35 years" answers the question of how long Mr. Bruns had been teaching. The verb is "teaching", and "for 35 years" modifies this verb.
According to what I know, B is the correct answer.
the answer to your question is stressful
Jim Crow law<span>. </span>Jim Crow law<span>, in U.S. history, any of the </span>laws<span>that enforced racial segregation in the South between the end of Reconstruction in 1877 and the beginning of the civil rights movement in the 1950s.
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The word showing this is cause and effect is "since."
Hope this helps!!