The correct answer is A. Putting a strict time limit on her studying
Explanation:
The main problem of Shauna is that she does not know when to stop studying; this implies, Shauna has problems in finding a limit which can cause Shauna only spends time studying but has no time for other responsibilities or leisure. In the same way, this type of behavior can lead to addiction to studying and later addiction to working which would affect negatively her life. Due to this, she must set a specific limit to study, in this way she can still study and achieve her goals but also know where to stop and spend time in other actives. Therefore, what would help Shauna to solve this problem is "putting a strict time limit on her studying".
The reason the deepest layer that this probe was able to directly sample is just the gaseous hydrogen layer is because Jupiter's upper atmosphere is about 88–92% hydrogen and 8–12% helium by percent volume of gas molecules. So the 200km this problem was able to cover is still composed of gaseous hydrogen.