Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 26 to 30.

The power of packaging

During the shopping trip to your supermarket, you will notice many similar products. How do manufacturers persuade you to buy their products and not those of another company? By careful packaging! Each of the boxes and bottles (26) ______ you see has been carefully designed to appeal to you, personally. Do you care about the environment? Then buy this washing powder; it contains (27) ______ chemicals. Do you want to impress your friends? Buy these trainers; they have a designer label. Before manufacturers market a new product, they spend months discussing the packaging. Then, they try out their ideas on a group of customers. Manufacturers (28) ______ customers will see more than just a box or bottle. They want to convince you that their product suits your personality more than any other products in the shop. One psychologist did some interesting research. He wanted to find out how (29) ______ packaging is. He asked customers to try a certain drink. They all agreed about the taste and quality. Then he secretly poured the same drink into a differently designed bottle. The results changed! People thought this drink tasted much better than the first, (30) ______ both drinks were, in fact, the same! To the researcher’s amazement, people’s opinions depended on the design of the bottle.

(26)........................

• A. 
  what
• B. 
  where
• C. 
  that
• D. 
  who