45. What is the conclusion of the study?

• A、Apple consumption has greatly reduced US adults' trips to the doctor.

• B、An apple a day does keep the doctor away.

• C、Apples are far more nutritious than oranges.

• D、A small number of US adult apple eaters tend to take less medicine.

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52. What does the underlined word "centenarians" in Paragraph 1 refer to?

• A、People who have secret lifestyles.

• B、People who enjoy physical exercise.

• C、People who are one hundred years old or older.

• D、People who carry the gene for being slim.