Question

read the passage.
finding bombs in germany
during world war ii, american and british forces dropped millions of tons of bombs on german cities. nearly ten percent of the bombs never exploded. the war ended in 1945, but more than two thousand tons of unexploded bombs are still found in germany each year. before any construction project is undertaken, the site must be checked for unexploded bombs. buried bombs are often discovered. for this reason, germany has a special force of firefighters and police officers, called the kmbd, to defuse and remove these bombs. even though the war has been over for seven decades, the kmbd is one of the busiest bomb squads on the planet.
what is the main, or central, idea of the passage?
because there are so many unexploded bombs in germany, the country has a special force trained to defuse them.
almost ten percent of the bombs dropped on germany during world war ii never exploded.

Explanation:

The passage first explains that many unexploded bombs from WWII remain in Germany (nearly 10% didn't explode, thousands of tons found yearly, checked before construction). Then it states Germany has a special force (KMBD) to defuse them. The first option captures the main idea by connecting the presence of unexploded bombs to the existence of the special force. The second option is just a detail about the bomb failure rate, not the main idea.

Answer:

Because there are so many unexploded bombs in Germany, the country has a special force trained to defuse them.