Mike: Bob zhǐ yòng le bàntiān de shíjiān jiù bǎ zhègè yóuxì wán tōngguān le.
Mike: Bob only used half a day to go through all levels of the game.
Lucy: Wa! Tā zhēnshì gè yìnghé wán jiā.
Lucy: Wow! He’s a real genius.
Mike tells Lucy that Bob is an expert in a game. We can use the context clues to learn about the sentence by looking at where Mike says “Bob只用了半天 (Bob zhǐ yòng le bàntiān)” and “玩通关 (wán tōngguān)”, which implies a game being done in a faster than usual time. Lucy responds in awe, when she says “哇 (wa)”, which implies that something extraordinary has happened.
Based on the conversation shown, we learn that Bob is very good at playing games, and that Lucy was praising Bob. Therefore, the best answer is A.