Sentence improvement — correct phrasal verb: use the reflexive idiom 'look after himself' in 'As he is past his teens now, he can look after himself.'

Given sentence
As he is past his teens now, he can look for himself.

Concept/Approach
The intended meaning is 'take care of himself'. The set phrase is look after oneself, not 'look for oneself' (which means 'search for oneself', illogical).

Option analysis
• after → 'look after (himself)' is correct.• 'to'/'around' → wrong particles for this meaning.• 'No improvement' keeps a semantic error.

Final Answer
after