Question: What information is **NOT** stored on the Universal Subscriber Identity Module (USIM) for Voice Group Call Service (VGCS), as per 3GPP specifications?
Option 1: Cipher algorithm for group IDs where data confidentiality may be applied
Option 2: Indications of whether the service subscriber can transmit application-specific data for each group ID
Option 3: Prefixes used in conjunction with group IDs
Option 4: Operator-specific additional information about the subscriber
Explanation: According to the specifications, when prefixes are used together with group IDs, these prefixes are not stored on the USIM. Additionally, any stored group IDs on the USIM do not include prefixes. This highlights an important aspect of how group call configurations are managed at the subscriber identity module level in telecom networks, emphasizing what is excluded from storage to maintain efficient and secure service provisioning.