Final answer:
The correct answer is C) 5th Marine Regiment and 6th Marine Regiment, which were instrumental in major WWI battles such as Belleau Wood, Soissons, and Blanc Mont Ridge.
Step-by-step explanation:
The two Marine regiments that were most instrumental in the battles of Belleau Wood, Soissons, and Blanc Mont Ridge during World War I were the 5th Marine Regiment and the 6th Marine Regiment. Option C) 5th Marine Regiment and 6th Marine Regiment is the correct answer.
These two regiments played a pivotal role in repelling the German offensive and turning the tide in favor of the Allies during the critical battles in the summer of 1918. Notably, the audacity and bravery displayed by the U.S. Marines in the three-week Battle of Belleau Wood, where they suffered heavy casualties, exemplified the fierce combat that ultimately contributed to halting the German assault.
These regiments, part of the U.S. 2nd Infantry Division, played a crucial role in these intense and pivotal battles on the Western Front. The Marines' resilience and bravery in the face of fierce German opposition earned them a lasting reputation for their tenacity and effectiveness in combat. The Battle of Belleau Wood, in particular, became a defining moment in Marine Corps history, solidifying their place as a formidable force in modern warfare.