The OPTION tag is a way for ILLiad to create unique values in an option list to be used for a dropdown selection. This tag is currently only used to specify the options for "Special Service" (which is a customization being phased out by newer options) or to create the list of valid accounts for a Borrowing web user.
If you have turned on billing for either Borrowing or Document Delivery, ILLiad must have a valid account selected for every request submitted. The accounts are unique to each user, though, so the drop down of choices would need custom values.
The OPTION tag to show the valid accounts for the logged in user would generally be on the request forms and edit request forms. These allow the one tag to translate to a user-specific list of accounts for the user. An example of how this tag would display in the HTML:
<select id="ValadminidAccountsDropDown" name="ValidAccountsDropDown" size="1" class="f-name"> <#OPTION name="ValidAccounts"> </select>
The name of the field used on request forms is ValidAccountsDropDown, but the name of the option within the OPTION tag is ValidAccounts.