
Unrestricted submarine warfare is a type of naval warfare in which submarines sink vessels such as freighters and tankers without warning, as opposed to attacks per prize rules (also known as "cruiser rules").
A should be it let me know the outcome
The use of aircraft had been useful in World War I. It may
not have been used as weapon however; the aircrafts were used to gather
information. There were also used as to look out for enemy camps. They used
message streamers in order to convey messages.
Answer:
A. the Oklahoma City bombing