The end tag can always be omitted.
|attribute name||possible values||meaning||notes|
|SELECTED||SELECTED||the option is selected by default||in a SELECT element without the MULTIPLE attribute, at most one OPTION element may have this set|
|VALUE||string||property value to be used when submitting the contents of the form; this is combined with the property name as given by the NAME attribute of the enclosing SELECT element||defaults to the contents of the element; however, several browsers ignore leading and/or trailing spaces in the content|
According to the HTML 2.0 specification, "the initial state has the first option selected, unless a SELECTED attribute is present on any of the OPTION elements". On the other hand, the HTML 3.2 Reference Specification leaves the default initial state open, so it is safest to assume that it is browser-dependent (and it actually is). You may wish to deal with this problem by providing a dummy first option (e.g. "No selection") and making it SELECTED, thus ensuring the same behavior from all HTML 3.2 conformant browsers. See Choices in HTML forms for more info.