What is the shape/design of a mandatory/command sign?

What is the shape/design of a mandatory/command sign?

1. Round sign with a double border around it: a thick red inner border, a thin white outer border, and a black symbol inside.
2. Square command sign with a thick blue inner border, thin white outer border, and a yellow symbol/sign inside.
3. A command sign with a round shape, a white border around it, a blue interior, and a white symbol or sign inside.

Correct answer

A command sign with a round shape, a white border around it, a blue interior, and a white symbol or sign inside.

This is the correct answer for the Cambodian driving theory test. Questions are drawn from the official Ministry of Public Works and Transport sign library and road rules.