A．variationB．varietyC．varianceD．variable

A. int

B. bool

C. double

D. array

As a _____ of our thanks, we will offer you two free round-trip tickets in first class to Hawaii.

A．symbol

B．badge

C．token

D．attribute

The use of music in supermarkets

A．may lead customers to pay more for a product.

B．can increase sales of a specific product.

C．makes people buy more foreign wine.

D．causes customers to buy more in the shop.