What is the rem unit based on?

1.  The rem unit is relative to the font-size of the p element.
2.  You have to set the value for the rem unit by writing a declaration such as rem { font-size: 1 Spx; }
3.  The rem unit is relative to the font-size of the containing (parent) element.
4.  The rem unit is relative to the font-size of the root element of the page.

Correct Answer:

•  The rem unit is relative to the font-size of the root element of the page.