Any field declared with keyword ________ is constant.

Which of the following is not a disadvantage of proxy servers?

a. Not all network services can be filtered. b. The proxy server can run slowly. c. Adding services can be difficult. d. There can be a potential problem with network failure if the proxy server fails or is corrupted.

A __________ can correspond to a machine instruction, as assembler directive, or a macro.

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