A healthy short-term goal refers to an objective that you can accomplish in the near future and that will allow you to have a good condition and avoid diseases. According to this, the answer is that the example of a healthy short-term goal is eat nutritious meals because it is a goal that you can accomplish in a short period of time and that will help you to be in a good physical condition.
The other options are not right because bench press an additional 100 pounds and lose 40 pounds are things that are not easy to accomplish in the short term and that can cause health problems if you do it quickly. Also, improve grades from one academic year to the next is a long term goal.