Neither First Lady Eleanor Roosevelt nor Secretary of Labor Frances Perkins sought recognition by the press, and both cautiously allowed others of the Roosevelt brain thrust to take credit for the genesis of historic programs in public employment, relief, and social security that were in large measure what they had been responsible for.

A. to take credit for the genesis of historic programs in public employment, relief, and social security that were in large measure what they had been responsible for
B. to take credit for the genesis of historic programs in public employment, relief, and social security for which the two women were in large measure responsible
C. taking credit for the genesis of historic programs in public employment, relief, and social security for which the two women were in large measure responsible
D. taking credit for the genesis of historic programs in public employment, relief, and social security that were in large measure what they were responsible for
E. taking credit for the genesis of historic programs in public employment, relief, and social security which were largely their responsibility

答案是A。我选的是B。

for which，what从句的使用有什么不一样？

in large measure的意思是什么?