not the company size or status.
If the HR person is very professional, you should feel lucky. It helps on the whole negotiation process, since you can behave simply professional as well, speaking out your mind and ask what you want straightforwardly but politely. An emotional HR person can be unpredictable, while one with tempers can be a disaster. "氣場很強大"? what does that really mean! Man, be afraid of nobody.
If you really want to join A, tell them. You can mention that you have offers from B and C and they will expire. You must emphasize that you really want to join A if they give you the opportunity. If they like you, they will try to speed up the hiring process.
You can also ask B and C for an extension for their offers. If they really want you to join them, they will. It is not easy to hire a good one.
