ANSWER

Step-by-step explanation
When a force is applied on an object of mass m, it produces an acceleration of a.
We can represent this relationship using Newton's second law of motion:

Now, the same force is applied on an object with a mass of 2m.
Let the acceleration experienced by the object be a1. This implies that:

We can write this new acceleration in terms of a as follows:

That would be the acceleration of the second object.
The answer is the third option.