Which method of communication is very popular and has reached in remote areas?

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E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart B (pp 233-449 of 464) p. 173-175
E6 Nursing_Management_and_leadership_Johny_Kutty_JosephCbs_Publishers (pp 16-364 of 374) p. 221-223
Practise the full AIIMS Raipur NO- 2019 (shift 3rd)
Attempt every question from this paper in a timed mock, then review the full solution for each one.