Please HELP ME !!


Choose the sentence that is written correctly.
A. Jason and Ethan went to the conference, they learned a lot about the new software.
B. Jason and Ethan went to the conference, and they learned a lot about the new software.
C. Jason and Ethan went to the conference and they learned a lot about the new software.
D. Jason and Ethan went to the conference when they learned a lot about the new software.