Concept:The blank needs a word that describes a person's mental outlook or approach toward using social media.
Explanation:The passage advises young users to build a healthy way of thinking about social media.
"Attitude" is the correct choice because it means one's mindset or perspective.
It fits the idea of having a balanced and positive approach while using social media.
Let us see why the other options are unsuitable:
"Habit" refers to a routine action, such as checking social media daily, but the passage talks about perspective, not behavior.
"Relationship" means a bond or connection between people or things, not a mental stance.
"Thought" means an individual idea or opinion, which is too narrow for the overall approach discussed here.
Only "attitude" correctly conveys the sense of a sustained mental approach.
Answer:Option A (attitude)