Final answer:
The subject of this question is projectile motion. The correct answer is free fall.
Step-by-step explanation:
The subject of this question is Projectile motion. When a rescue plane drops a package to a stranded party of explorers, the package will undergo projectile motion. Projectile motion occurs when an object is launched into the air and moves in a curved path under the influence of gravity.
In this case, the package is dropped from the plane and will move in a curved path due to the force of gravity. It will not accelerate horizontally, but only vertically. The package will fall freely without any external forces affecting its motion, such as air resistance, since it is stated that it is dropped in the absence of air resistance.
A is the correct answer: Free fall.