19Where it is determined by agreement or an award that the owners of a bridge are to contribute to the expense of a highway authority, the contribution shall, at the option of the owners of the bridge, be paid—
(a)as a lump sum, or
(b)by annual payments of such amount, and continuing for such number of years, as may be agreed between the owners and the authority or, in default of agreement, as may be determined by arbitration, or
(c)by perpetual annual payments of such amount as may be so agreed or determined.