The two events that were instrumental in the United States entering World War II are:
C. The bombing of Pearl Harbor
F. The United States intercepted the Zimmerman Telegram
However, it's important to note that while the Zimmerman Telegram was significant in the context of World War I, the most direct catalyst for the United States entering World War II was indeed the bombing of Pearl Harbor on December 7, 1941. The Lend-Lease Act (option A) also played a significant role in shaping U.S. involvement before the formal entry into the war but is not an event that directly led to the U.S. entering World War II. The others (B, D, E) do not pertain to the U.S. entry into World War II.