How can you do this?

You purchase materials from a third party supplier for sale and delivery to your customers. You want to ensure that creation of a sales order automatically results in the creation of a purchasing document .

How can you do this? Note: There are 2 correct answers to this question.
A . Use an item category in which the Item Relevant for Delivery field is set.
B. Use a sales document type in which the Reference Mandatory field is activated.
C. Use a schedule line category in which a purchasing document type is specified.
D. Use an item category in which the Schedule Lines Allowed field is activated.

Answer: C,D