Read the text, and choose the best answer for the following questions 

Mind-blowing facts about modern communication

The Internet holds about 5 million terabytes of data. That’s about the same as 1 million human brains. According to experts, there are about 2 billion Internet users in the world. 70% of people in developed countries go online, but only 20% of people in developing countries can access to the Internet.

The average Internet user has 25 online accounts and logs in 8 times a day. 30% of Internet users have just 1 password for all their online accounts, and the most common password is “password1”. About 55% of users choose words which have some personal meaning, and 15% write down both their password and username.

Many people use Wi-Fi hotspots in public places, such as café, airports and hotels. 46% of them are worried about viruses and hackers. Many people type in personal information while using public Wi-Fi: 22% regularly type in email passwords, 21% log onto Facebook and 8% do online banking, but they are unaware about how to be totally secure.

The first computer virus appeared in 1981. The first virus to affect mobile phones appeared in 2005. And the first anti-virus software came out in 1990. There are now about 6,000 new computer viruses every month.

87% of Internet users go online with their smartphone at least once a day. About 80% keep their smartphone turned on 24-7 and 23% use it during mealtimes.

500,000,000 people in the world have a Facebook account – that’s about one in every 13 people. The average user has 130 “friends”, and 48% of adults check their Facebook page as soon as they wake up in the morning. Every 20 minutes, Facebook users around the world upload 2,716,000 photos.

How many Internet users are there in the world?

• A. 
  half a billion
• B. 
  one billion
• C. 
  two billion
• D. 
  four billion