Question: For which User Equipment (UE) categories is the 'multiTone-r13' field, related to UL multi-tone transmissions on NPUSCH, specifically applicable and mandatory according to the latest specifications?
Option 1: UE Category-M
Option 2: UE Category-NB and UE Category-M
Option 3: All UE Categories (e.g., M, NB, 1, etc.)
Option 4: UEs of any ue-Category-NB
Explanation: The correct answer is specifically tied to UEs of any ue-Category-NB, as this is the category for which the 'multiTone-r13' field is defined and mandated in the context of UL multi-tone transmissions on NPUSCH. This highlights the importance of understanding specific UE categories and their capabilities within telecom networks, particularly in relation to nuanced transmission protocols like multi-tone transmissions.