Explanation:

Let’s break down the options:

- Option 1: Tricks to capture an empire

- Dharmasutras do not provide strategies for political conquest or empire-building.

- Option 2: Norms for women only

- Dharmasutras have guidelines for all sections of society, including men, women, students, and rulers—not just women.

- Option 3: Techniques to recite shlokas

- They are not about chanting or recitation techniques; that would be covered in texts on pronunciation and grammar.

- Option 4: Norms for rulers

- Dharmasutras mostly contain rules and guidelines for righteous behavior, duties, laws, and norms for rulers and society. They define the ethical and legal codes for various roles in society, including rulers.