IX. Several senior officers of the Armed Forces of the Philippines received invitations from the Chairperson of the Senate Committees on National Defense and Security for them to appear as resource persons in scheduled public hearings regarding a wide range of subjects. The invitations state that these public hearings were triggered by the privilege speeches of the Senators that there was massive electoral fraud during the last national elections. The invitees Brigadier General Matapang and Lieutenant Coronel Makatuwiran, who were among those tasked to maintain peace and order during the last election, refused to attend because of an Executive Order banning all public officials enumerated in paragraph 3 thereof from appearing before either house of Congress without prior approval of the President to ensure adherence to the rule of executive privilege. Among those included in the enumeration are "senior officials of executive departments who, in the judgment of the department heads, are covered by executive privilege." Several individuals and groups challenge the constitutionality of the subject executive order because it frustrates the power of the Congress to conduct inquiries in aid of legislation under Section 21, Article VI of the 1987 Constitution. Decide the case. (5%)