What characteristics does Miako's credit card exhibit with a 1.9 percent introductory rate that changes to "prime plus 9 percent" after 12 months?

The characteristics of Miako's credit card include both teaser rates and variable interest rates.

A teaser rate, often used as a promotional strategy, is an initial low interest rate offered for a limited time—in this case, 1.9 percent for the first 12 months. This rate is designed to attract consumers and incentivize them to sign up for the card by providing a lower cost of borrowing initially.

After the introductory period, the card's interest rate changes to "prime plus 9 percent." This change signifies a variable interest rate, as it is directly tied to the prime rate, which can fluctuate based on broader economic conditions and monetary policy. Therefore, the interest experienced after the introductory rate is contingent upon changes in the prime rate, making it a variable rate.

Since the card exhibits both features—the initial low promotional rate and the subsequent variable rate based on the prime rate—it is correct to say that it embodies both teaser rates and variable interest rates.