When do I need US visa?

I have a valid visitor’s visa (B1/B2) and I am traveling to the U.S. on a short-term business or tourist VWP program?
No, you will be traveling on a visitor visa.

I do not have a visitor’s visa and I am traveling to the U.S. on a VWP program for a short-term business or tourist visit?
Yes.

I don’t have a visitor’s visa, but I have another type of visa, such as a student visa (F1), but I am traveling on VWP for short-term business or tourism purposes?
Yes.