What characterizes an item category in purchasing?

Besides manual creation, how can you create source list entries? (Choose two.)

How can you clear a balance on the GR/IR clearing account if the invoiced quantity is higher than the delivered quantity?
There are 3 correct answers to this question.
Response:

You post a valuated goods receipt for a purchase order. The material has a material master record and a material type for which quantity and value are updated.
The purchase order item has the account assignment category K (= cost center). After the posting, you check the accounting document. To which G/L accounts were the postings made?
There are 2 correct answers to this question.
Response:

Which procurement element can be created in Purchasing with automatic purchase order generation?
Please choose the correct answer.
Response: