"Master' and 'Slave' are obsolete and misleading terms which were useful back in the days of MFM drives, but which should not be used on modern HDDs and SSDs. Let's rethink slightly:
/dev/sda1 Linux 731 MB
/dev/sda2 LVM 38.4 GB
/dev/sdb 5.1 GB you need to create a partition before use
/dev/sdc 10 GB you need to create a partition before use
/dev/sdd 11.7 GB you need to create a partition before use
In order to copy files to /dev/sdb , /dev/sdc . or /dev/sdd , you need to partition them, using the rules of VirtualBox, to complete the process of making them virtual disks, and then mount them in the virtual instance of Ubuntu 16.04 . Once you've done that, you can use Ubuntu's cp command to copy, or use its File Manager to drag-and-drop or select-copy-paste.