Analyze the relationship between 'Boko Haram' and 'Abubakar Shekau' within the context of the input sentence.
Options: chairperson, creator, headquarters location, location of formation

Leader of the Boko Haram sect, Abubakar Shekau has again resurfaced in a recording and denied claims by Chadian … see more » Copyright © 2015 Premium Times.
chairperson