Explanation:

- Section 91 of the Indian Penal Code (IPC): Consent is valid for actions causing harm to the consenting person, otherwise deemed an offence. However, offences that are independently criminal irrespective of harm or consent, aren't excused by consent.

- Option 1: Offences against public safety

- These are crimes regardless of personal consent, as they endanger society.

- Example: Carrying a firearm in public without a license can't be consented to lawfully.

- Option 2: Causing miscarriage to a woman

- It's illegal and considered an offence against the unborn child, irrespective of the woman's consent, except in some medical circumstances.

- Option 3: Mischief

- This offence involves causing damage or harm to property and isn't independently criminal without harm or consent implications.

- This option isn't fitting the principle of Section 91.

- Option 4: Public nuisance

- This affects the community's rights at large and can't be consented to by an individual.

- Correct Answer: Option 3

- This option does not exemplify acts independently criminal without consent consideration.