Answer:
Mandy practiced karate every day, yet she failed to beat her final opponent.
Step-by-step explanation:
The subordinating conjunction that can complete this sentence is one that can join two contrasting ideas: “Mandy practiced karate every day” and “she failed to beat her final opponent”. From all options, “yet” is the correct option because it means “but” or “nevertheless” and one of its functions is to join two different ideas.
The other options, on the other hand, are incorrect because “in order to” is used to express the purpose of something, “if” introduces a conditional clause or hypothetical situation, and, lastly, “while” means “during the time that” or “at the same time as.”