Which document must soldiers complete for educational programs under the Army Continuing Education System?

The correct document that soldiers must complete for educational programs under the Army Continuing Education System is the DA Form 87. This form, known as the "Certificate of Training," is utilized to record both formal training and informal education and helps to ensure that soldiers are recognized for their accomplishments in educational pursuits. By completing this form, soldiers can document their participation in various educational programs, which is essential for maintaining accurate records of their continuous learning and professional development.

Other forms listed serve different purposes within military operations. For instance, the DA Form 31 is used for requesting leave, while the DA Form 2807-1 is a medical history form required for various assessments. The DA Form 4126 is used for specific administrative actions related to enlisted personnel. Thus, while these forms are important in their respective contexts, they do not pertain directly to educational programs under the Army Continuing Education System.