Which of these statements completes the diagram? A) poison gas
B) atomic bombs
C) guerilla warfare
D) covert operations

the correct answer would be A poison gas,as mustard gas were used to kill many soldiers during WW1.

b, public works good luck

the answer to fill in the blank in this question would be the word resource, it is defined as the money, material or people (since human resource is a very valuable good) that a company or a person has at disposition (meaning they can use the resource as they see fit), to be able to complete a task or achieve a goal.