【单选题】Teenagers are spending more money than ever. Just last year, 31.6 million teens spent 155 billion, according to the Northbrook, Illinois-based market research group Teenage Research Unlimited. Much of...
A.
a market research company based in Illinois
B.
a spokesman for the Teenage Research Unlimited
C.
the base of the Teenage Research Unlimited
D.
the city where the spending survey was carried out