What is most surprising is that it was not (4) ........... earlier, although the great inventor Leonardo da Vinci had drawn picture for bicycle and also for flying machines and some other things.

Read and choose the best option A, B, C or D to complete the passage.

Bicycles

The bicycle is one of the simplest yet most useful inventions in the world. What is most  surprising  is  that  it  was  not  (4) ........... earlier, although the great inventor Leonardo da Vinci had drawn picture for bicycle and also for flying machines and some other things. Those things were not produced until long after he died.

A person riding a bicycle use very little energy to make the bicycle move, and there is no pollution at all when you are riding. Even so in developed (5) .........., most people don’t travel to work by bicycle. It is not because the bicycles are expensive or people feel (6) ......... if they ride to work. It’s because (7)........ cars on the roads becomes larger. It certainly becomes (8) ........... to ride a bicyle. As a result, more people put their bicycles away and go to work (9) .......... their cars, and in this way, the situation is made more serious. (10) ........... the best way to make riding safer and more popular is to create paths only for bicycle and to make it so difficult and expensive for drivers to their cars into the city that they will go back to use their bicycles.

(4) ...............

• A. had
• B. used 
• C. invented
• D. ridden