What open source port-scanning tool is considered to be the standard port-scanning tool for security professionals?

If a class represents an amount of money (in US currency like $9.99), then the amount (like $9.99) could reasonably be stored in

a. A member variable of type double. b. Two member variables of type int. c. A string of characters (like "9.99"). d. None of the above.

What type of protocol is implemented at the level of the device's operating system, allowing the device to support both IPv4 and IPv6, either as independent protocols or in a hybrid form?

A. dual-stack B. dual-architecture C. hybrid D. transition