Mike's Dress Mart Calls a Manufacturer and Offers to Purchase

Mike's Dress Mart calls a manufacturer and offers to purchase 100 dresses specifying a particular style number and asking for assorted sized in blue and red.The manufacturer can only accept this offer:

A) by returning the phone call and verbally agreeing.
B) by sending a written signed letter agreeing to the terms.
C) by sending a written signed contract agreeing to the terms.
D) by immediately shipping the 100 dresses in assorted sizes in red and blue.
E) All of the above would constitute a valid acceptance.