How is gravity "best" described? options:

a description of mass

a molecular pull

a kind of acceleration

a fundamental force

a fundamental force

Explanation:

Gravity is the only fundamental force that physicists can currently describe without using force-carrying particles.

Gravity is best described as a fundamental force.

Explanation:

Gravity is one of the 4 fundamental forces(3 of the forces out of 6).  

The description of mass is independent to Gravity. Since an objects mass determines the strength of the pull of Gravity. But it is not Gravity itself.

Molecular pull is more of a density determination. For example the pull between the atomic particles of a solid is stronger than those of a gas.

Thrust is a kind of acceleration. It is the push and resist to the drag force.