Motivating? Motivative? Motivational?

Hello, could anyone tell me which one among them is good or bad? When something motivates me to learn Enlgish, I wonder how to say it properly. Is it motivating/ motivative/ motivational?.
I know that motivating is correct. but I don't know the other two, and don't know the difference, either. I looked them up in a dictionary, and it wasn't helpful. So, please help me!