Question: What is the characteristic of the password used for controlling a supplementary service by a subscriber, as supported by the network?
Option 1: Alphanumeric string with a minimum length of 8 characters
Option 2: A 4-character static code predefined by the network operator
Option 3: A dynamic one-time password sent to the User Equipment (UE) via SMS
Option 4: A numeric code consisting of exactly 4 digits, ranging from 0000 to 9999
Explanation: This is correct because, according to specifications for supplementary services, when a subscription option allows control using a password, the network supports passwords that are specifically defined as being exactly 4 digits long, within the range of 0000 to 9999. This ensures a standardized and manageable level of security for subscriber-controlled supplementary services.