Which is the jQuery selector for 'select' option list when I'm using JQuery.find

I'm trying to get the value of select option that is inside a table, so I did a for each row but when I try to get the value of select it return undefined. I would like to know if .find('select option') is the correct parameter for .find() selector. I post code below.

$('#checklist tbody tr').each(function() {
    conceptos.push($(this).find("td").eq(0).html());
    if ($(this).find("td").eq(3).find('input[type="checkbox"]').is(':checked')) {
        conceptos.push(1);
    } else {
        conceptos.push(0);
    }
    //alert(JSON.stringify($(this).find("td").eq(4)));
    conceptos.push($(this).find("td").eq(4).find('select option').val());
});
alert(conceptos);