Final answer:
The advanced search option among the given options is Filter by filetype. This option allows users to filter search results based on the type of file format they're looking for.
Step-by-step explanation:
The advanced search option among the given options is Filter by filetype.
This allows users to filter search results by the type of file format they're looking for. For example, if a user wants to find only PDF files, they can select the 'PDF' option from the filter.
Other search options, such as Filter by language and Filter by date, are commonly available search filters but may not be considered as advanced options as they are more commonly found in search engines.