A. Correct. Full immersion most of the time, yes, but probably not always. The New Testament doesn't mention infusion, pouring water on the forehead, but it seems a more likely method for the baptizing of 3,000 people on Pentecost. The Didache written before the end of the second century advises "if youu have no running water... pour water on the head."

 

B. Incorrect. "Always"? Probably not.