When selected, the ________ field property requires that each record contain a value not found in any other record

Raina complains to Marc that her smartphone seems to be warped or something and now her back cover doesn't seem to sit right. What is the problem?

A) Water has penetrated the case. B) The battery needs to be replaced. C) The system needs a factory reset. D) Marc has put the wrong smartphone backing on.

Navigation doesn’t just make it easy to get to content: it also gives you a way to see what the site contains at a glance.

What will be an ideal response?