Answer: C. I took the one less traveled by,/And that has made all the difference.
Explanation: In this excerpt from "The Road Not Taken" by Robert Frost, the option that best shows that the speaker made an uncommon decision is "I took the one less traveled by...". The author refers in this poem to the choices in life. When we are forced to make decisions we can choose the mainstream or take a road less traveled by and be alone. It is obvious that his decision was to take the less traveled road.