Lewis Offers to Make Digital Copies of Motivational Sales Company's

Lewis offers to make digital copies of Motivational Sales Company's business conference videotapes, CDs, DVDs, and other media for $500. Under the mailbox rule and the UETA, Motivational Sales' acceptance by e-mail will be considered effective when

A) received.
B) sent.
C) followed up by a confirmation letter sent by regular mail.
D) composed on a Motivational Sales computer.