Choose the correct answer: based upon based by based in based at

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 23 to 27.

The Microscope

One of the most important inventions in the development of science and medicine was the microscope. It  was  (23)  _________ the  principle  that  light  could  be  “ refracted ”  or  bent,  by  a  glass  lens.  It  was  soon discovered  that  tiny  objects  could  be  magnified  (24)  _________  size  when  viewed  through  a  glass  lens  that had been ground and polished in a specific (25) . _________  Although the principle was known to the Chinese as  early  as  1000 A. D,  it  was  not  until  the  13th  and  14th  centuries  in  Europe  (26)  _________  it  was  put  to practical use in the form of eyeglasses.
In  Europe  the  first  microscope  was  invented  by  brothers  Zacharias  and  Hans  Janssen,  two  Dutch eyeglass-makers, around 1590. They built a “compound” microscope, so called because of its two lenses. The  most  significant  development  and  use  of  the  microscope  during  this  period,  however,  belongs  to another  Dutch  optician,  Antonie  van  Leeuwenhoek.  Bom  in  Delft,  Holland,  he  became  skilled  at  (27)  _________ very sharp and accurate magnifying lenses.

• A. based upon
• B. based by
• C. based in
• D. based at