Question: Which of the following were key doctrinal problems arising from WWI?
A. How to achieve a tactical penetration of enemy defenses without sustaining heavy casualties and to simultaneously deploy a mobile reserve force to secure the breach.
B. How to reduce a complex obstacle belt in order to secure a breach for mobile infantry and artillery and destroy the subsequent enemy counterattack.
C. How to achieve a tactical penetration of enemy defenses and then translate that into operational success by defeating an army through the depth of its formations.