(D) E-mail spam, also known as junk email, is unsolicited messages sent in bulk by email(spamming). The name comes from Spam luncheon meat byway of a Monty Python sketch in which Spam is ubiquitous,unavoidable and repetitive.Email spam has steadily grown since the early 1990 s, and by 2014 was estimated that it made up around 90% of email messages sent.