Quiz: searching and editing text

Read the output

The log has lines with timeout and with refused. Why did grep print nothing?

$ grep 'timeout|refused' app.log
$ echo $?
1

• A grep cannot search for two words in one command.
• B The words in the log are written in capitals.
• C grep took the quoted pattern for a file name.
• D Without -E, | is an ordinary character to grep, so it searched for the text timeout|refused as a whole.