Question: What international recommendation's data numbering plan should the structure of Mobile Station International Data Numbers comply with, specifically in the context of a mobile subscriber's home country?
Option 1: ITU-T Recommendation X.500
Option 2: ITU-T Recommendation X.121
Option 3: 3GPP TS 23.070
Option 4: E.164 Numbering Plan
Explanation: The correct answer is ITU-T Recommendation X.121 because the structure of MS international data numbers must align with the data numbering plan outlined in X.121, particularly within the mobile subscriber's home country, ensuring interoperability and consistent numbering practices globally.