The first sentence is correct.
The answer is: a)
The central idea refers to what the text is mainly about.
The author uses the character of Torvald Helmer to explore a social issue B) By revealing attitudes related to spending and saving that many men held during the Victorian era.
During the Victorian Era, in which this work is set, people ruled their lifestyle by preserving money and finding their best way to face economical problems. They worked hard to get and keep what they had, and this can be clearly reflected in Torvald Helmer's attitudes about borrowing money.
