Step 1: Understanding the Concept:
The sentence requires an adjective derived from the base word 'care'. The context implies a negative quality that needs to be "controlled". We need to choose the suffix that creates an adjective with the appropriate negative meaning.
Step 2: Key Formula or Approach:
Analyze the meaning created by each suffix when added to 'care'.
- careful: (with the suffix -ful) means taking care, being cautious. This is a positive trait.
- careless: (with the suffix -less) means lacking care, being negligent or thoughtless. This is a negative trait.
- carefree: (with the suffix -free) means free from worries or responsibilities. While this can sometimes be viewed negatively, 'careless' more directly implies a behavior that needs to be controlled.
- notcare: '-not' is a word, not a standard prefix or suffix to form an adjective in this way.
Step 3: Detailed Explanation:
The sentence talks about a "nature of the youngsters" that "should be controlled". This points to a negative characteristic.
- A 'careful' nature would be praised, not controlled.
- A 'careless' nature, meaning a lack of attention and thought, is something elders would seek to control.
- A 'carefree' nature might also be a concern to elders, but 'careless' is a stronger and more fitting word for behavior requiring control.
Therefore, the word 'careless' is the most appropriate fit for the sentence. The required suffix is '-less'.
Step 4: Final Answer:
The correct suffix is '-less' to form the word 'careless', which fits the negative context of the sentence. This corresponds to option (B).