Kenneth's manager has been receiving complaints that kenneth is rude when he's conversing over email. which email etiquette has kenneth violated? a he sent big files as attachments. b he hasn't specified the intent of the email in the subject field. c he hasn't been direct while writing his email. d he didn't check for grammatical and spelling errors. e he didn't use the proper tone in the emails he writes.

The correct answer is E. He didn't use the proper tone in the emails he writes.

Explanation:

Etiquette in email communication and similar contexts includes a set of rules that guarantee communication is effective and polite. In the case of proper tone, this refers to the attitude the person writing the message conveys, this can be polite, unpolite, honest, rude, etc. Additionally, the tone depends on the words used as well as other elements, for example not including a salutation might be interpreted as rude for many people.

According to this, Kenneth has probably violated the rule of using a proper tone because people complaints he seems rude in his email messages. This means, he probably did not use the appropriate words or elements and convey a negative attitude or tone.