Which of the following sentences is the least formal in style?
A. I gained significant experience with computers while attending college.
B. I gained a lot of experience with computers while I was a student in college.
C. I have a lot of experience with computers from my college days.
D. I've got a ton of experience with computers from school.
D does not use complete words to explain and also uses the word “ton” which is informal in nature as compared to other sentences.
Therefore, the Correct Answer is D.