What kind of BGP path attribute is AS_PATH?

An autonomous system has 7 routers configured with BGP. How many iBGP sessions are required for a fully meshed configuration?

A BGP router receives the following routes. Which route is selected as best route?

1: 192.169.20.0/24 with local preference 100, MED 150, AS Path 65300 65200 from an eBGP neighbor

2: 192.169.20.0/24 with local preference 100, MED 100, AS Path 63200 from an iBGP neighbor

3: 192.169.20.0/24 with local preference 200, MED 150, AS Path 65400 63200 from an iBGP neighbor

4: 192.169.20.0/24 with local preference 200, MED 100, AS Path 63700 from an eBGP neighbor