Which sentence best states the idea that this excerpt to develop?

Letter B would be correct.

The author first talks about how people were promised in marriage around their early ages, 'still in their cradle', in the second half of the 15th century ('That was about 1470').

Then, 2 centuries later (17th Century), women of high and middle class in society were still promised to men, with few exceptions. And these men they were promised to were entitled as lords and masters

And he concludes stating that women from authentic literature of that time (Shakespeare's included) weren't represented as powerless as they were in real life.

in our power to make a world happy - to teach mankind the art of being so - to a character hitherto unknown - and to have, as it were, a new creation intrusted to our hands, are honors that command reflection, and can neither be too highly estimated,