John Has Opened a Text File Named Data

Multiple Choice

John has opened a text file named data.txt in the vi editor. He moves the cursor using the arrow keys to a position in the file where he needs to make several changes. However, when he tries to enter text nothing happens. Which of the following could be stopping John from entering text?

A) The vi editor is in insert mode. He needs to switch to command mode.
B) The vi editor is in insert mode. He needs to switch to replace mode.
C) The vi editor is in command mode. He needs to switch to insert mode.
D) The text file is corrupt.