What is a preview statement? Why should the introduction of a speech nearly always include a preview statement?

The Sapir-Whorf hypothesis of linguistic relativity states that:

A) previous histories have been characterized by an unjust distribution of suffering. B) the power and beauty of languages move people emotionally and stir them to action C) all languages are similar at the core. D) the structure of a culture's language shapes what people think and do.

In a job interview, what you do may be just as important as what you say

Indicate whether the statement is true or false