Questions Refer to the Documents Below

Questions refer to the documents below.
Document A. Trench Warfare, World War I Document B. Dulce et decorum est* (Excerpt) , Wilfred Owen (1918)
Bent double, like old beggars under sacks,
Knock-kneed, coughing like hags, we cursed through sludge,
Till on the haunting flares we turned our backs
And towards our distant rest began to trudge.
Men marched asleep. Many had lost their boots
But limped on, blood-shod. All went lame; all blind;
Drunk with fatigue; deaf even to the hoots
Of gas-shells dropping softly behind.
*translation: From the Latin phrase "Dulce et decorum est, pro patria mori"
"It is sweet and fitting to die for one's country."
-Document B describes the effects of:

A) an attack by the new weapon, tanks.
B) forced marches to cover the long distances to the front.
C) chemical warfare and poison gas.
D) sleep deprivation from long periods at the front.