; (III) official trade statistics of the United States International Trade Commission; and (IV) other relevant data sources, including those described in paragraphs (5) through (7); (D) to identify any issues with verifying the average product emissions intensity data for covered products produced in each covered country; and (E) to determine the relative average product emissions intensity of each category of covered products produced in the United States compared to the average product emissions intensity of each category of covered products produced in each covered country. (2) Prioritization (A) In general Subject to subparagraph (B), in conducting the study under paragraph (1), the Secretary shall complete all elements of the study described in subparagraphs (A) through (E) of that paragraph within the applicable 2- or 5-year timeframe. (B) Prioritization due to data or time constraints If completion of all elements described in subparagraphs (A) through (E) of paragraph (1) with respect to a study under that paragraph is precluded by data or time constraints, the Secretary shall adhere to the applicable 2- or 5-year timeframe by prioritizing the study of— (i) higher priority categories of covered products, as described in subparagraph (C); and (ii) higher priority covered countries, starting with those that are among the 5 largest global exporters or the 5 largest sources of imports into the United States. (C) Order of priority described The order of priority described in subparagraph (B)(i) is as follows: (i) First, categories of covered products subject to international border carbon adjustment mechanisms, such as the Carbon Border Adjustment Mechanism of the European Union, including the categories of covered products described in each of— (I) clause (i) of subsection (a)(4)(B) (aluminum); (II) clause (ii) of that subsection (articles of aluminum); (III) clause (iii) of that subsection (articles of cement); (IV) clause (iv) of that subsection (articles of iron and steel)