In order for a research source to be useful, its author(s) must have a) bias. b) credentials. c) refutations. d) salaries.

In order for a research source to be useful, its author(s) must have credentials (B).

Let's define some words:

Bias- prejudice in favor or against something

Credentials- a quality, achievement, personal quality, or aspect of a person's background that determines if they are suitable for something

Refutations- the action of proving something to be true or false

Salaries- what someone is paid

its he tried to add or forgive me but he said forego

the answer to the blank is recite