<span>The Chinese, who made flags from silk, began using them more than 3,000 years ago.
The adjective clause is "who made flags from silk" it describes the Chinese. Another helpful clue is that it begins with "who".
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ANSWER FOR YOUR QUESTION
The Central Pacific Railroad (CPRR) was a rail company chartered by U.S. Congress in 1862 to build a railroad eastwards from Sacramento, California, to complete the western part of the "First Transcontinental Railroad" in North America. Incorporated in 1861, CPRR ceased operation in 1885 when it was acquired by Southern Pacific Railroad as a leased line.
I believe the correct answer is: B) Neighborhood Leaders Request an Inquiry About Pollution.
Option B seems to be the most neutral of the given choices and doesn't change the overall meaning of the title. Option A doesn't sound neutral and options C and D change the meaning of the headline.
Pyro involves heat, I don't know if that's one of your options though