Out of the given options, choose the one which can be substituted for the given phrase\ sentence:

'Work for which no regular salary is paid'

Honorary

The correct answer is Option (2) → Honorary

"Honorary" refers to a position or work done without receiving a regular salary, often as a mark of respect or recognition.

• Option (1) → Ad hoc: Means temporary or formed for a specific purpose, not necessarily unpaid.

• Option (3) → Honourable: Means deserving of respect, not related to unpaid work.

• Option (4) → Temporary: Refers to something not permanent, but it can still be paid.