Which country became the first to suspend the use of the video-conferencing tool Zoom by teachers on Apr 11,2020?

A. Srilanka
B. Singapore
C. Malaysia
D. China

Singapore bans teachers using Zoom after hackers post obscene images on screens. Singapore has suspended the use of video-conferencing tool Zoom by teachers after “very serious incidents” in the first week of a coronavirus lockdown that has seen schools move to home-based learning.
One incident involved obscene images appearing on screens and male strangers making lewd comments during the streaming of a geography lesson with teenage girls, media reports said.