What happened to daily life as soldiers on both sides realized that no one could gain an advantage ...

What happened to daily life as soldiers on both sides realized that no one could gain an advantage in trench warfare?
 
  a. Savage treatment of prisoners became commonplace.
  b. New weapons were developed to kill rather than overrun the enemy.
  c. Soldiers' daily lives became increasingly squalid and miserable in rat-infested trenches.
  d. Officers increasingly encouraged soldiers not to fight and to await a peace treaty.
  e. Most of the participants on all sides simply quit active fighting and the war bogged down into a stalemate.