What are the default layout options available in Magento ?

No layout updates – By default, layout updates are not available for Product/Category/CMS pages.
Empty – By default, uses a blank layout for Product/Category/CMS pages.
1 column – By default, uses a single column layout for Product/Category/CMS pages.
2 columns with left bar – By default, uses a two-column layout with the sidebar on the left for Product/Category/CMS pages.
2 columns with right bar – By default, uses a two-column layout with the sidebar on the right for Product/Category/CMS pages.
3 columns – By default, uses a three-column layout with sidebars on the left and right for Product/Category/CMS pages.
Page – Full Width – By default, uses the Page – Full Width layout.
Category – Full Width – By default, uses the Category – Full Width layout.
Product – Full Width – By default, uses the Product – Full Width layout.