Answer:
Option C, The complete history of breast cancer is now known
Explanation:
A research conducted on breast cancer would help in the following ways -
a) A complete history of this medical issue can be determined.
b) Based on the history, probable causing agents or cause of the disease can be determined.
c) Research could help us in finding ways for its early detection
d) Already existing medication practices can be improvised and new medicines can be produced.
hence, option C is the correct answer