Three questions

Sample sentences:
1a. To keep China's economy running in a proper range is the basic demand of China's current macro-control, as well as the middle and long term orientation of the policy in China.
1b. To keep China's economy running within a proper range is both a basic target of China's current macro-control and its medium-to-long term policy goal.

Hi. I'm doing a translation exercise. 1a is my version and 1b is the reference version.

1. Do you think my use of "orientation" in my sentence makes sense?

2. Why use “a” here in 1b? Can I use “the”?

3. Do both “within” and “in” work here?
Thank you.