Light Pollution I Grew Up in the City, a Place So Full

Light Pollution
I grew up in the city, a place so full of streetlights, spotlights, and searchlights that the sky was never dark enough to see the Milky Way. But last year, I went on a camping trip through the Grand Canyon. When I saw the night sky for the first time, I was in awe. I could not believe how many stars there were.
As cities push farther and farther into the wilderness, they create light pollution, the brightening of the night sky by artificial light sources. Light pollution not only hinders our ability to see the beauty of the stars, but it might be causing other problems as well.
Light pollution also disrupts the lives of certain animals. For example, too much artificial light can prevent newly-hatched sea turtles from finding the ocean. Owls and other birds that hunt at night can injure themselves by flying into brightly lit buildings.
So what is the solution? Obviously, we cannot turn off all of the lights every night. But we can reduce the amount of light we send into the sky. Homeowners should use motion sensors on outdoor lights. Cities should turn off (or at least dim) streetlights after midnight. Businesses and office buildings should turn off their lights when they close for the day. Turning off the lights will help animals and restore the night sky to its former glory.
Question: What is the main idea of the passage?

A) Light pollution can be caused by streetlights, spotlights and searchlights in the sky.
B) Something must be done to end night pollution, which brightens the night sky and disrupts the lives of animals.
C) People should reduce the amount of light that they send into the sky by using motion sensors on all outdoor lights.
D) Night skies that are too bright can prevent recently hatched turtles from finding the ocean.