Beginning in the 2018–2019 school year, each county board is encouraged to implement an agriculture science curriculum specified in subsection (b) of this section in: At least one public high school in the county; or At least one career and technology education center in the county. The agriculture science curriculum implemented under subsection (a) of this section shall be: Selected from existing curricula that have been developed by the Department; or Developed by a county board and approved by the Department.