Analyze the relationship between 'Boko Haram' and 'Abubakar Shekau' within the context of the input sentence.
Options: parent organization, legal form, chairperson, product/material produced

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