Option C
Explanation
<?xml version="1.0" encoding="UTF-8"?>
This line is called XML Prolog .
The XML prolog is optional. If it exists, it must come first in the document.XML documents can contain international characters, like Norwegian øæå or French êèé.To avoid errors, you should specify the encoding used, or save your XML files as UTF-8.UTF-8 is the default character encoding for XML documents.
source : W3schools XML Syntax