Don't tell the call spammers this or they'll train all their "agents" to start phone calls with "what's up, bro" or something they think is the stereotypical opposite of formal.
The second one is almost always used by Healthcare companies in my experience, in a backwards attempt at HIPPA compliance.
They want to make sure they called the right person. Except they know everyone hates getting called like this, so they take "who is this?" as affirmation and then proceed to tell you their company and the call.