**Explanation:**

Notices are written for various purposes and can cover a wide range of topics. However, option 'C' is the correct answer because notices are commonly written to inform about lost property. Let's discuss each option in detail:

**a) An event:**
- Notices can indeed be written to inform about an event. For example, if a school is organizing a sports day, a notice can be written to inform the students, parents, and staff about the event.
- Such notices typically include details about the event, such as the date, time, venue, and any specific instructions or requirements. They also serve as a reminder for people to mark their calendars and attend the event.

**b) A programme:**
- Notices can also be written to announce a programme or an activity, such as a cultural performance, a workshop, or a seminar.
- These notices provide information about the programme, including the theme, the participants, the schedule, and any registration or ticketing requirements.
- They aim to attract the attention of the target audience and encourage their participation or attendance.

**c) A lost property:**
- Notices are commonly used to inform others about lost property. People often post notices in public places, such as community boards, to seek help in finding their lost belongings.
- These notices typically include a description of the lost item, the date and location it was lost, and contact information for the owner.
- They serve as a means of spreading the word and increasing the chances of the lost property being returned to its rightful owner.

**Conclusion:**
While notices can be written for events and programmes, option 'C' is the correct answer because notices are frequently used to inform about lost property. These notices aim to seek assistance from the public in recovering the lost belongings by providing relevant details and contact information.