Coverage A (Dwelling) insures the dwelling on the residence premises, structures attached to it, and materials and supplies on or next to the residence premises used to build, alter or repair the dwelling or other structures.
Land is not covered, including the land the dwelling sits on. California's residential disclosure makes the same point: dwelling limits do not cover the value of your land.
Coverage B (Other Structures) covers structures on the residence premises set apart from the dwelling by clear space, including those connected only by a fence, utility line or similar connection, such as a detached garage or a tool shed.
Coverage B does not cover:
structures rented to someone who is not a tenant of the dwelling, unless used solely as a private garage;
structures from which a business is conducted.