Question: Under what condition can the network include the Backup Bearer Capability Information Element (IE) in a message?
Option 1: When there are multiple Bearer Capability IEs contained in the message.
Option 2: When the MSC is able to provide a complete Bearer Capability IE.
Option 3: When the MSC has previously used the Backup Bearer Capability IE.
Option 4: When there are no Bearer Capability IEs contained in the message.
Explanation: The network can include the Backup Bearer Capability IE only if there are no Bearer Capability IEs contained in the message, as specified in the standard. This is to ensure that the backup capability is used only when the primary bearer capability information is not available.