Nancy asks her mother if she can have three cookies before dinner, and her mother says "no." Nancy then asks if she can have just one cookie before dinner and her mother says "yes." Nancy's dual requests BEST illustrate which of the following

The answer is door-on-the-face technique.

Explanation:

This persuasion technique consists in asking for a large request followed by a smaller one. The listener is more likely to comply to the second, smaller request.

An explanation for this technique is that the person requested feels socially responsible of complying.