[单项选择]

阅读理解：请根据短文内容，为每题确定l个最佳选项。
A New Strategy to Overcome Breast Cancer。

Post-menopausal（绝经后）women who walk for an hour a day can cut their chance of breast cancer significantly,a study has suggested. The report, which followed 73,000 women for 17 years,found walking for at least seven hours a week lowered the risk of the disease.The American Cancer Society team said this was the first time reduced risk was specifically linked to walking. UK experts said it was more evidence that lifestyle influenced cancer risk.

A recent poll for the charity Ramblers a quarter of adults walk for no more than an hour a week,but being active is known to reduce the risk of a number of cancers.This study, published in Cancer Epidemiology,Biomarkers&Prevention,followed 73.615 women out of 97,785 aged 50-74 who had been recruited by the American Cancer Society between 1992 and 1993,so it could monitor the incidence of cancer in the group.

They were asked to comp
A. chief editor of Cancer Epidemiology.
B. chair of the American Cancer Society.
C. head of the survey study.
D. chief executive of Breast Cancer Campaign.