閱讀下文，回答第41－43題

Chart One shows how adults at risk of internet addiction attempt to prevent it. In comparison, Chart Two shows how parents try to stop their underage children, who already overuse the internet, from becoming addicted.

Chart One: the adult group
62.50% No methods adopted
21.40% Developing offline activities or hobbies
5.00% Setting a daily internet use time limit
4.40% Finishing tasks before internet entertainment
4.30% Monitoring daily internet usage
3.80% Others
1.90% Restricting internet use after bedtime
1.30% Setting internet use limits on a cellphone or tablet
0.20% Declining to answer
0.10% Using digital tools to track online behavior

Chart Two: the parent group
52.00% Setting a daily internet use time limit
16.90% No methods adopted
10.90% Children's cellphones only used during permitted times
9.30% Encouraging offline activities and interests
8.90% No cellphone use by children
8.80% Family-agreed internet time and interactions
6.90% Using software to manage children's internet usage time
5.70% Having children finish tasks before going online
4.80% Tracking children's internet activity and time
4.30% Others
0.30% Declining to answer

41. What is the main purpose of these two charts?

(A)The types of online events people like to attend.

(B)The reasons why people become addicted to the internet.

(C)The digital tools whose features attract different internet users.

(D)The methods people use for the prevention of internet addiction.