According to Thomas Cook and Dan Campbell, is often the best available approximation of the truth or falseness of an inference, proposition, or conclusion.

Answer is Validity.

Explanation:

Validity can be described or explained by assertion of information.

Validity has important function, because it helps people to know that the information that was provided has value. This means that the information or statement provided is not false.

Thomas Cook and Dan Campbell also explain that the validity of an information can also be ascertained by providing and letting readers have access to the sources of references.

"harry t. moore (1905-1951) – civil rights activist, leader, and the first martyr of the civil rights movement. fannie lou hamer (1917–1977) – leader in the american civil rights movement; co-founder of the national women's political caucus and freedom democratic party. james farmer (1920–1999) – congress of racial equality."