No option of 3200x1800 resolution on my virtualbox linux

I just installed a xubuntu system on my virtualbox. I installed guest additions for virtualbox, but I do not have the option to resize the screen to 3200x1800, as i have a 4k res screen. Is 4k supported in virutalbox, and if so, how do i set my linux distro to 4k? Thank you

Know someone who can answer? Share a link to this question via email, Twitter, or Facebook.