untangling the history of Christmas lights

Question

Which detail from the text demonstrates the popularity of Christmas tree lights?
A. "Johnson turned his stunt into a tradition; he also pioneered the practice of doing more each year: An 1884 New York Times article counted 120 bulbs on his dazzling tree." (Paragraph 5)
B. "Johnson's lights were indeed ahead of their time — electricity was not yet routinely available — and they weren't cheap." (Paragraph 6)
C. "A string of 16 vaguely flame-shaped bulbs sitting in brass sockets the size of shot glasses sold for a pricey $12 (about $350 in today's money) in 1900." (Paragraph 6)
D. "Today an estimated 150 million light sets are sold in America each year, adding to the tangled millions stuffed into boxes each January." (Paragraph 7)

Answer 1

The detail that demonstrates the popularity of Christmas tree lights is:

D. "Today an estimated 150 million light sets are sold in America each year, adding to the tangled millions stuffed into boxes each January." (Paragraph 7)

This statement indicates the widespread usage and popularity of Christmas lights in contemporary society.