All bids for construction work shall be presented under sealed cover and shall be accompanied by one of the following forms of bidder`s security: (a) Cash. (b) A cashier`s check made payable to the district. (c) A certified check made payable to the district. (d) A bidder`s bond executed by an admitted surety insurer, made payable to the district. Upon an award to the lowest bidder, the security of an unsuccessful bidder shall be returned in a reasonable period of time, but in no event shall that security be held by the district beyond 60 days from the time the award is made.
