Question

the battle of the coral sea introduced a new kind of warfare in which
troops were transported to islands by plane.
battles took place in plain view of each other.
airplanes were used to attack opposing ships.
ships were used to attack opposing airplanes.

Explanation:

The Battle of the Coral Sea was a naval battle in World War II where aircraft carriers played a key role, and airplanes were used to attack opposing ships (the ships themselves were often out of direct visual range, and the attack was via aircraft). The first option is incorrect as it's not about troop transport by plane in this battle context. The second is wrong as battles weren't in plain view (they were at sea with aircraft as the main attack medium). The fourth is incorrect as ships' primary role wasn't attacking opposing planes directly in this new warfare context; it was planes attacking ships.

Answer:

C. airplanes were used to attack opposing ships.