Which of the following is the reported speech of the direct speech below? “Don’t use emojis in your e-mails when writing formally to someone!” he warned us.

He warned us not to use emojis in your e-mails when writing formally to someone.

He warning us not to use emojis in our e-mails when writing formally to someone.

He to warned us not to use emojis in our e-mails when writing formally to someone.

He warned us to use emojis in your e-mails when writing formally to someone.

He warned us not to use emojis in our e-mails when writing formally to someone.