Question: In the context of the EFORPK (Operator Root Public Key) file in a USIM, what is the primary purpose of the "Type of certificate" field (coded as a binary value: 0, 1, or 2)?
Option 1: To indicate the size of the key/certificate data.
Option 2: To specify the offset into the Key/certificate Data File.
Option 3: To identify the type of certificate containing the key (e.g., WTLS, X509, X9.68).
Option 4: To determine if a record is full and which optional parameters are present.
Explanation: The "Type of certificate" field is crucial for identifying the format or standard of the certificate that contains the Operator Root Public Key. This information is vital for proper verification and processing of the certificate within the USIM, especially when dealing with different types of certificates (e.g., WTLS, X509, X9.68) that may have distinct handling requirements in telecom networks.