Question

read the excerpt from woman in the nineteenth century by margaret fuller.
yet, then and only then will mankind be ripe for this, when inward and outward freedom for woman as much as for man shall be acknowledged as a right, not yielded as a concession. as the friend of the enslaved man assumes that one man cannot by right hold another in bondage, so should the friend of woman assume that man cannot by right lay even well - meant restrictions on woman. if the enslaved man be a soul, if the woman be a soul, apparelled in flesh, to one master only are they accountable.
how does fuller develop an argument for womens rights?
by describing the strength of womens friendships
by making reference to a biblical lesson
by insisting that everyone with a soul deserves rights
by explaining the history of slavery

Explanation:

Fuller emphasizes that if women (and enslaved men) are souls, they should have rights. The key idea is that having a soul (a fundamental aspect of being human) entitles one to rights. She uses the parallel of the enslaved man's right to freedom (as a soul) to argue for women's rights. The other options - describing women's friendships, referencing a biblical lesson (not clearly done here), or explaining slavery history - are not the main way she builds her argument in this excerpt.

Answer:

by insisting that everyone with a soul deserves rights