In the context of postal regulations for business correspondence, which of the following statements is true about business letters, postcards, business reply cards; letters weighing less than 13 ounces; sealed and unsealed, handwritten or typed material?
A) All types of correspondence listed can be sent using the same postage rate regardless of weight or format.
B) Business reply cards must be sent with a return postage fee pre-paid by the sender.
C) Letters weighing less than 13 ounces can be sent at first-class mail rates, whether they are sealed or unsealed and handwritten or typed.
D) Postcards and business reply cards are only eligible for standard mail rates if they are sealed and contain typed material.