The correct subordinating conjunction is "yet" and the sentence is completed as follows:
Mandy practiced karate every day, yet she failed to beat her final opponent.
The word "yet" is a subordinating conjunction that means "nevertheless" or "however", it is associated with negative statements in order to mention that an event did not take place.
In this sentence, it explains that even though Mandy had practiced she did not beat her opponent.
The second one, and the last one
The best answer to the question that is being stated above would be the sentence that is numbered one (1): 'When it comes to fiction, there are many genres'. The next sentences are only subtopics and only support the main idea that are lots of genres for fiction.