The correct answer is D. Emoticons or smileys.
Emoticons or smileys are used in an e-mail to express emotions or feelings clearly. They are small images or symbols that are used to convey a feeling or emotion. For example, the smiley face emoticon (:) is used to express happiness or joy.
Acronyms are words that are formed from the first letters of other words. For example, the acronym LOL stands for “laughing out loud.” Abbreviations are shortened forms of words or phrases. For example, the abbreviation BTW stands for “by the way.” Rich text is text that includes formatting such as bold, italics, and underline.
While acronyms, abbreviations, and rich text can be used to express emotions or feelings, they are not as clear or concise as emoticons or smileys. Emoticons or smileys are also more likely to be understood by the recipient of the e-mail.