Answer:
C. The abilities of boys are better than those of girls
Step-by-step explanation:
This book was written by Elizabeth Cady Stanton, who was a famous women rights activist in the late 19th century.
That information alone could be enough to understand the theme of the book. But, let us carefully examine this excerpt.
The key piece of information here is: "... a girl weighed less in the scale of being than a boy.."
That sentence sums up society's views in the 19th century; a girl is less important, less valued, less appreciated and considered less capable then a boy.