A. Definitely not. Please remember that IELTS essay writing is not a test of how many difficult words you write. Rather, it is a test of your writing skills that must have coherence and clarity. Even if you memorize “high-level” words, you will not know whether they can be used in the text or not. Having a strong vocabulary definitely helps, especially in paraphrasing, but it is just one of the scoring criteria. Your focus must be on writing an essay that has a flow where all the points are connect to each other via logic.