I think the correct answer would be B. Descartes' work can be best describe as he is the the one who proposed that through the use of reason and doubt individuals may arrive at understanding. He destroyed all sources of knowledge for him to reach the certainty of knowledge called the Radical-Methodic doubt. He argues that knowledge would always start with doubting. Through this belief, it lead to the phrase "Cogito ergo sum" or I think, therefore I am was which is a very famous quote used. From the said quote he was able to make other philosophical ideas which includes the existence of God.