Answer:
The correct option is "Gravity is an acceleration of about 10 m/s/s that acts downward on a freefalling object"
Step-by-step explanation:
Gravity can be described as a force of attraction between two bodies or a force that planetary bodies use to pull objects towards themselves. The latter description is the one been tested in the question.
The acceleration due to gravity on earth is 9 m/s² which is the same as 9 m/s/s. Because gravity is a force of attraction, hence it can only be said to act downward on a free-falling object and NOT upwards (as that would no longer be attraction but repulsion).