Mathematical symbols used in building expressions

After an EIGRP router sees a Hello from a neighbor, what parameter(s) does the router not check before establishing a neighbor relationship?

A) Must be on same subnet B) Must be using the same hello timer and dead timer C) Must be using the same AS number D) The source IP address used by the neighbor's Hello must be in the same subnet.

What methods of the String class are inherited?

What will be an ideal response?