答案解析：
B
整段对话其实是在说 baby 的性别是什么，而作为父亲的 Ross 不想知道。但是 Monica 知道了，后来他告诉了 Joey。

听力原文：

Rachel: (to Ross) I can't believe you don't want to know. I mean, I couldn't not know, I mean, if, if the doctor knows, and Carol knows, and Susan knows....
Monica: And Monica knows...
Ross: Wha, heh, how could you know, I don't even know!
Monica: Carol called me to thank me for the lasagna, I asked, she told me.
Joey: So what's it gonna be? (Monica whispers in Joey's ear. Ross gets up and waves arms frantically in protest)
Ross: Wait—oh—hey—huh, oh great now he knows, and I don't know!
Monica: I'm sorry, I'm just excited about being an aunt!
Joey: Or an uncle...