Final answer:
The phrase "Sign up now!" is a Call to Action in marketing, which aims to prompt an immediate response or sale.
Step-by-step explanation:
The phrase "Sign up now!" is an example of a Call to Action (CTA) in marketing. A CTA is designed to prompt an immediate response or encourage an immediate sale. Unlike an advertising slogan, which is meant to be memorable and establish brand identity, or a marketing strategy, which is an overarching plan, a CTA is a direct instruction aimed to provoke an immediate reaction from the potential customer.