First and foremost, it's 'argument'.
It depends on what type of argument you're talking about. There really isn't a black and white view to whether it's equivalent to debate or more or less positive than conversation.
In its simplest terms, argument is just stating reasons for your beliefs. Whether you realize it or not, everyone uses it often in everyday life. For instance, "I think Japanese is a cool language, as..." would be an argument.
So basically, it can be equally or more positive than conversation, because you might be more interested and involved with something rather than just everyday talk.
But, sometimes two people can have a large disagreement over something. Then it can get negative when they use an aggressive tone, e.g. "That's ridiculous! What on Earth are you talking about? This clearly supports what I think..." There's a solution to this though - reaching a middle ground, where both sides are happy.
And about whether it's equivalent to debate, once again, it depends. Often 'debate' is reserved for controversial and heated topics whereas trivial matters like "Why is sushi so tasty?" would not be a debate. But then again, it's all subjective and people can use 'debate' for everything involving discussion.
So there you go. And for the record, I voted 'Other'.