Every grant issued by the Board of Playground Commissioners under this article shall prescribe:
(a) That upon the expiration thereof all groins, jetties, breakwaters, sea walls, pipe lines, sewers, piers, wharves, buildings or other structures shall become and be the property of the City, with or without compensation therefor, as the particular grant may declare, or
(b) That the grantee or holder thereof shall have the privilege, or be compelled to remove the groin, jetty, breakwater, sea wall, pipe line, sewer, pier, wharf, building or other structure, at their own expense, and said grantee may or may not retain the materials used in the construction, as the particular grant may specify.