Read the following passage and circle the letter A, B, C or D to indicate the correct phrase or clause that best fits each of the numbered blanks. (1.0 point)

The Best 20th-Century Invention

            The mobile phone is one of the most important inventions of the 20th century. It was invented in the 1970s. At first, mobile phones were big and (15) _______. Now those phones are in museums! Things have changed a lot for the past decades! (16) _______ are small and very smart. They work like mini computers. People can use them to send messages, (17) _______, play games, and much more. Some phones are very expensive, but there are also cheaper ones that almost everyone can afford. Because of this, mobile phones are everywhere now. In my opinion, this is why the mobile phone is the best invention of the 20th century. (18) _______ because it has transformed how we connect with each other.

It was invented in the 1970s. At first, mobile phones were big and (15) _______.