Which method advocates the use of already acquired language skills in the mother tongue to develop and achieve fluency and accuracy in the learning of target language?

Correct option is B

Grammar Translation method.
The Grammar Translation method is a traditional language teaching approach that emphasizes the study of grammar and translation. In this method, learners are taught the grammatical rules of the target language and then practice translating sentences from their native language to the target language. While the Grammar Translation method may not be as effective as some other methods for developing fluency, it does emphasize the importance of accuracy.