Which statement is true of the single colon (:) or double colon (::) notations for pseudo-elements-for example, ::before and :before?

1.  All browsers support single and double colons for new and older pseudo-elements. So you can use either but it is convention to use single colons for consistency.
2.  In CSS3, the double colon notation (::) was introduced to create a consistency between pseudo-elements from pseudo-classes. For newer browsers, use the double colon notation. For IE8 and below, using single colon notation (:).
3.  Only the new CSS3 pseudo-elements require the double colon notation while the CSS2 pseudo-elements do not.
4.  In CSS3, the double colon notation (::) was introduced to differentiate pseudo-elements from pseudo-classes. However, modern browsers support both formats. Older browsers such as IE8 and below do not.

Correct Answer:

•  In CSS3, the double colon notation (::) was introduced to differentiate pseudo-elements from pseudo-classes. However, modern browsers support both formats. Older browsers such as IE8 and below do not.