In every interview you must be clear about when you will make your decision, and when they will. It's basic politeness not a negotiating tactic. When A calls yo

In every interview you must be clear about when you will make your decision, and when they will. It's basic politeness not a negotiating tactic. When A calls you back, tell them thanks and that you will let them know by X. When dealing with B, tell them that you will make your decision by X as well. If A want an answer now, be firm but polite. If they want you they'll wait. If they think you are a dime-a-dozen they won't. Better to find that out now. In the future make date X clear from the getgo.