Who Said That?

Test your quote IQ! Who said this?
 
“I think, therefore I am.”
 
A. Marcus Aurelius
B. Gautama Buddha
C. René Descartes
D. Nicolas Cage
With hundreds of witticisms, musings, disses, words of inspiration, and canny observations, all wrapped up in the form of an addictive game with different ways to play, Who Said That? Is the most fun you can have while actually getting smarter. Or to put it another way, where else would you find Albert Einstein, Mother Teresa, Jay-Z, Bill Clinton, Patti Smith, Charlie Brown, Muhammad Ali, Lena Dunham, Joan Didion, Oprah Winfrey, and Henry David Thoreau all hanging out together?
Answer: C