Write a multi-choice question for the following article, with the given choices and answer: Article: It's our hope that the calculator will promote action, awareness and empowerment by showing you that one person can make a difference and help stop global warming. There are many simple things you can do in your daily life--what you eat, what you drive, how you build your home--that can have an effect on your immediate surroundings, and on places as far away as Antarctica. Here is a list of things that you can do to make a difference. Use Compact Fluorescent Bulbs Replace 3 frequently used light bulbs with compact fluorescent bulbs. Save 300lbs (pounds) of carbon dioxide and $60 per year. Use Recycled Paper Make sure your printer paper is 100% post consumer recycled paper. Save 5lbs of carbon dioxide per ream of paper. Take Shorter Showers Showers account for 2/3 of all water heating costs. Save 350 lbs of carbon dioxide and $99 per year. Buy Products Locally Buy locally and reduce the amount of energy required to drive your products to your home. Carpool When You Can Own a big vehicle? _ with friends and co-workers saves fuel. Save 790 lbs of carbon dioxide and hundreds of dollars per year. Don't Idle in Your Car Idling wastes money and gas, and generates pollution and global warming causing emissions. Except when in traffic, turn your engine off in you must wait for more than 30 seconds. Buy Organic food The chemicals used in modern agriculture pollute the water supply, and require energy to produce. Turn Off Your Computer Shut off your computer when not in use, and save 200 lbs of carbon dioxide. Conserve energy by using your computer's "sleep mode" instead of a screensaver. With a Stop Global Warming calculator which costs you only $50 in hand, you will find what you do does count. Options: A Giving people tips on how to save money in life B Telling people how to be environment-friendly C Promoting the product "Stop Global Warming calculator" D Telling people how to prevent carbon dioxide from being released Answer: C Promoting the product "Stop Global Warming calculator" Question:
The answer to this question is:
What is the purpose of the author writing this passage? _ .