Hello Douglas,

No, the “Reset this PC” will not remove the partitions, it will only modify the partition where Windows is installed.
To set things straight, you must either perform a clean install of Windows 10 or use a tool like EaseUS Partition Master.

You could use the partition manager built into windows but I think EaseUS Partition Master which is free will be better suited as you can preview your changes before actually applying them.

You can click here for more information using EaseUS Partition Master to delete and merge partitions.

Please make a complete backup of any data you care about before trying.