A school sends a notice only through an online platform although some families lack internet access. Which barrier does this illustrate?

Correct answer: Inaccessibility of the medium

A communication channel is effective only if intended receivers can access and use it. Families without internet cannot receive the notice through the chosen platform, so the problem is the inaccessibility of the medium, often associated with a digital divide. It is not primarily an emotional, accent, or personal-prejudice issue. An accessible alternative channel would reduce the barrier, making D correct.