Part A
The main claim the author makes in the passage is:
4. Sometimes it is necessary to pass good but unpopular laws.
Part B
The detail from the passage that best supports the correct answer from Part A is:
3. "But not one of them would have been made to this day if it had been necessary to wait until the majority of women asked for it." (Paragraph 2)
This statement indicates that significant reforms for women were made without majority support, illustrating the need for necessary changes to be enacted even when they are not widely popular.