Final answer:
The British and the French developed a secret weapon called landships (tanks) during World War I to cross no-man's land.
Step-by-step explanation:
The subject of this question is history.
The correct answer is b. Landships.
During World War I, the British and the French developed armored vehicles known as landships, which were later renamed tanks. These tanks were initially designed to overcome the challenges of crossing no-man's land and the trench warfare of the time.
Learn more about Development of landships in World War I