Which company cofounder of Twitter developed a system for mobile credit card payments for small businesses?

• A. Square
• B. Stripe
• C. Adyen
• D. Worldpay

Answer: (A)

The concept tested is recognizing the person who, beside co-founding Twitter, built a mobile card payment system for small businesses. Square fits because it was created by Jack Dorsey, a Twitter cofounder, to let small merchants accept credit card payments using a simple card reader plugged into a smartphone and a companion app. This approach made payments portable and affordable for small businesses, revolutionizing how they handle card transactions on the go.

The other names are well-known payment platforms, but none are tied to a Twitter cofounder as their origin story. Stripe focuses on online payments and developer APIs, Adyen serves large-scale merchants globally, and Worldpay is a long-established processor.