Question: In a 3GPP Generic Bootstrapping Architecture (GBA) scenario, what capability is required from the User Equipment (UE) when both a USIM and an ISIM are present for bootstrapping?
Option 1: Automatically default to using the USIM for bootstrapping.
Option 2: Prioritize the use of the ISIM over the USIM for all GBA procedures.
Option 3: Select either a USIM or an ISIM to be used in bootstrapping, based on indication from a Ua application on the Mobile Equipment (ME).
Option 4: Require the user to manually switch between USIM and ISIM for different bootstrapping sessions.
Explanation: This option is correct because it aligns with the specified requirement that the UE must have "the capability to select either a USIM or an ISIM to be used in bootstrapping, when both of them are present" and further refines this by noting the selection can be based on an indication from a Ua application on the ME, highlighting the integration with application-level decisions for bootstrapping. This showcases the UE's flexibility in handling multiple subscription identities (USIM/ISIM) based on application needs, which is crucial for managing different services or identities within a single device.