What key trademark of TSA was developed by Steve Price in 1989?

The logo is a key trademark of the Technology Student Association (TSA) that was developed by Steve Price in 1989. A logo serves as a vital visual representation of an organization, helping to create brand recognition and identity. The TSA logo symbolizes the organization's focus on technology education and student leadership, making it an essential element that aligns with TSA's purpose and mission. A distinct and well-designed logo helps to unify members under a common image and is often associated with pride in membership and participation in various TSA activities.

The other items listed, such as the motto, creed, and mission statement, contribute to the organization’s identity and values but are not specifically credited to Steve Price in the same way the logo is. Thus, the logo stands out as a core component of TSA's branding, making it the correct answer to this question.