I want markup tags in xml as value?

I am working on a plugin that sends something as value,it is a shipping plugin for joomla.

<param name="" type="list" label="something"        description="something">
 <option value="<tag>some value</tag>">a</option> //XML Parsing Error at 38:29. Error 73: > required
                <option value="">b</option>
</param>