。
I'll take care of it.
Literal
I [subject-が] care [object-を] see.
が emphasizes the speaker as the one taking responsibility — 'I will (not someone else).' Using が rather than は in a self-assertion highlights that the speaker is uniquely volunteering for the task, often heard when stepping forward in a group. 面倒を見る ('to take care of, look after') is the fixed idiom — literally 'see the trouble.'