For dealing with difficult words in the text, a language teacher first converts the words into mother tongue and then asks the students to memorise it. She is using :

Correct option is A

Grammar translation method.
The grammar translation method is a traditional method of teaching foreign languages that focuses on memorizing grammar rules and vocabulary translations. It is not an effective method for teaching reading comprehension, as it does not help learners to develop the skills they need to construct meaning from text.