Hello, I have some basic questions about Assets

First, what is preferred market pairing? It is found under the Description of the asset.
I want my asset to be tradeable directly to and from Bitcoin. in other words, I want users to register an OpenLedger account, deposit Bitcoin to their account and then have the option to buy my asset using the Bitcoin they deposited. So would I put something in this field to expedite that?

How do you distribute dividends to the purchasers of your coin? I want to specify: "Even though my OpenLedger account holds X amount of Bitcoin, take Y amount of my Bitcoin and distribute it to all holders of my asset proportional to the amount of units of my asset they hold. "

Can an asset be deleted once created?

What is a Smart Coin?