What is the meaning of the idiom "writing on the wall"?

a.
messages left for people one knows

b.
a sign that something bad is about to happen

c.
children's drawings and scribbling

d.
a warning of danger to keep people away

it’s important not to respond to the bully because doing so generally just escalates the problem.

tell a trusted adult about what is happening and save the evidence. you should also let your internet or cell phone provider know, along with the operator of the site if it is happening online.

if the bullying continues, notify the local police and consider consulting an attorney if it becomes serious.

school authorities may also become involved if it involves students on campus.