; and (iii) to the extent possible, maintains or restores existing natural slopes and connections between uplands and adjacent wetlands or surface waters; and (B) may include, but not be limited to, the use of— (i) natural elements, such as sand, wetland plants, logs, oysters or other shellfish, submerged aquatic vegetation, native grasses, shrubs, trees, or coir fiber logs; and (ii) structural materials, such as stone, concrete, wood, vinyl, oyster domes, or other approved engineered structures. (4) State The term State means each of the several States, the Commonwealth of Puerto Rico, the United States Virgin Islands, Guam, American Samoa, the Commonwealth of the Northern Mariana Islands, and each Federally recognized Indian Tribe. (g) Authorization of appropriations There are authorized to be appropriated $20,000,000 to the Administrator for each of fiscal years 2018 through 2023 for purposes of carrying out this section.