<p>I would recommend option #3 - which is to just do a single major, and take that extra time you would have spent in getting another major, and instead using it to do more undergrad research, i.e. actually trying to get something published in major journal. </p>
<p>Instead of spending an extra year in college getting a double major, I would just take a job doing something science-related for a year. Either that, or get a master's degree in that year. </p>
<p>The truth is, the return-on-investment on getting multiple majors is pretty low. Most people who go on to getting their Phd's do not have multiple majors. And after you get a graduate degree (master's or PhD), nobody is really going to care what you did in undergrad anyway.</p>