When used with the String type, the plus (+) symbol performs a(n) ____ operation.

Due to the nature of dual-stack operation, when IPv6 is the preferred protocol, the pings are successful via __________.

Fill in the blank(s) with the appropriate word(s).

public static int Abs(int) Which of the following would be a valid call to the above method?

A. answer = Abs(-23); B. answer = int Math.Abs(-23) C. answer = Math.Abs(-23) D. answer = int Abs(-23)