Because Many Email Programs Display the First Few Words or Lines

Because many email programs display the first few words or lines of incoming messages, you should

A) be vague in your first sentence, to entice the reader to open the message.
B) leave several blank lines at the beginning of each message.
C) treat the first sentence of the message as an extension of your subject line.
D) use phrases such as "MUST READ" in your first sentence.