To delete a variation and all its options:

1. Edit an existing product
2. In Variations section, find the variation you want to delete. Click Trash Delete Icon
3. Confirm by clicking on Delete

To delete a specific variation option: 

1. Edit an existing product
2. Find the variation of which option you want to delete. Click Pencil Edit Icon
3. Find the option you want to delete in Options section. Click Trash Delete Icon
4. Confirm by clicking on Delete. Repeat to delete additional options
5. Click Update