What is the minimum screen diagonal for a tablet used as an electronic learning device?

Question

What is the minimum screen diagonal for a tablet used as an electronic learning device?

Answer choices

1. At least 26.6 cm.
2. At least 21.6 cm.
3. At least 31.6 cm.

Explanation

In the Russian sanitary requirements tested by this question, a tablet used as an electronic learning device in an educational organisation must have a screen diagonal of at least 26.6 cm.

This is the diagonal of the screen, not the width of the tablet's casing. The correct choice is 26.6 cm.