Read the following text and mark the letter A, B, C or D on your answer sheet to indicate the correct option that best fits each of the numbered blanks from 16 to 20.

The word "robot" was first used in 1920. It comes from the Czech word 'robota', (16) ________ means 'forced labour' used in a play by Karel Čapek to describe artificial people. In 1949, the British inventor William Grey Walter introduced the first machine which could slowly move in (17) ________ to light stimulus. The first robot to use Artificial Intelligence was known as Shakey. Twenty years later, a walking robot called Dante, which was (18) ________  of climbing steep slopes, was built to go into active volcanoes. The late 1990s marked a (19) ________ in the history of robots when Kismet, a robotic head designed to provoke and react to emotions, was created. Since the beginning of the 21st century, more robots have been created to improve our life. The first self-driving car was launched on 8 October 2005. In 2012, the Al expert Geoffrey Hinton and his team created the first accurate visual recognition system. In 2016, Sophia, a human-like robot was introduced. Sophia can (20) ________ human gestures and facial expressions and is able to answer certain questions and to make simple conversations.