Answer:
A). By exploring the benefits of living with no debt.
Step-by-step explanation:
The authors often employ characters as their mouthpiece to show the social context and social issues prevailing at the time text is being drafted. Similarly, Nora in 'A Doll's House' is employed as the author's representative to give an insight into the social issue like 'restriction of women to stereotypical roles' in society.
As per the question, the author uses Nora to explore the social issue by 'exploring the benefits of living with no debt' as it assists to have a respectful and dignified life(for men). The money here is representative of the power and this is explored by the author portraying Torvald's authority over Nora as he wanted to live a life with no-debt(male-dominated society didn't want women to interfere in terms of money and wanted their roles to be restricted to household chores only).
It displays the dual-standards of the society by portraying the difficulties personified by Nora who struggles to develop an 'individual self' of her own. This reflects that women were denied being a part of the world of men that mirrors the dual-faced nature of the society towards two genders(one of the major social issues). Thus, option A is the correct answer.