To determine the correctness of the given statements about the CMS-03 communication satellite, we must evaluate each statement based on current knowledge and available information.

1. Statement A Analysis: "CMS-03 was launched by LVM3's 4th operational flight on November 20, 2025."
   • As of October 2023, there is no recorded or planned launch of a satellite named CMS-03 by India's GSLV Mk III (LVM3) on November 20, 2025. This suggests that the date mentioned in the statement is speculative or incorrect.
   • Furthermore, historical records show that the launches of the CMS series communication satellites (such as CMS-01, CMS-02) have been successful, but the specific detail about LVM3's 4th operational flight for CMS-03 is fictional in the context of the current timeline.
2. Statement B Analysis: "CMS-03 is a multi-band communication satellite that provides services over a wide oceanic region including the Indian landmass."
   • The description of CMS-03 as a multi-band communication satellite aligns with the typical specifications and objectives of similar satellites in the CMS series launched by ISRO.
   • The purpose of these satellites often includes providing critical communication coverage over the Indian ocean region and the Indian subcontinent to enhance telecommunication capabilities.

Based on the analysis of both statements, the correct option is:

Statement B is true, but Statement A is false.