Correct option is C
No error in the given sentence structure. The sentence correctly uses the conditional form "If I were" followed by the result "I would have taken care," which is grammatically correct.
Grammatical rule used: The use of "would have taken care" correctly implies an action that would have been done in the past, under a hypothetical condition stated by "If I were your mother."
Example: If I were the manager, I would have handled the situation differently.