Which of the Following Types of Study Have Led to the Introduction

Which of the following types of study have led to the introduction of a population‐ based screening programme for the cancer in question?

A) Randomised trials of prostate cancer screening
B) A cross‐sectional study of mammography accuracy
C) Case‐control studies of mammography and breast cancer deaths
D) Randomised trials of 'Pap' smears for cancer of the cervix
E) Descriptive studies of mortality trends for colorectal cancer (CRC)
F) Noneoftheabove