; and (II) not later than December 21, 2020, conduct a national exercise to test the preparedness and response of the Nation to the effect of an EMP or extreme GMD event. (C) Research and development (i) In general The Secretary, in coordination with the heads of relevant Sector-Specific Agencies, shall— (I) without duplication of existing or ongoing efforts, conduct research and development to better understand and more effectively model the effects of EMPs and GMDs on critical infrastructure (which shall not include any system or infrastructure of the Department of Defense or any system or infrastructure of the Department of Energy associated with nuclear weapons activities)