Question no 2851 : Validity Period in Purchasing Document

In SAP MM ECC6.0 EhP6, validity period in the header purchase order is a feature of which of the following purchase order scenario ?

(moret han one answers)

A)   Subcontracting Purchase Order.
B)   Purchase aorder with an ERS indicator.
C)   Invoicing Plan.
D)   Blanket PO.
E)   Framework Order.
.