8. Read the underlined sentences, then choose the best answer to the question or the best completion of the statement.

Some stores are testing a new checkout system that allows shoppers to use their mobile phones to scan items as they walk through stores and pay at self-service kiosks, skipping the cashiers' lines.

The new mobile checkout system reduces long lines and customer wait times in stores.

What does the second sentence do?

A. It expands on the first.
B. It contrasts with the first.
C. It states an effect.
D. It gives an example.