Concept: Section 80 of the Code of Civil Procedure requires notice before institution of a suit against the Government or a public officer in respect of an act done in official capacity.
Step 1: Understand Section 80 CPC.
Before filing a suit against the Government or a public officer, a notice must generally be served.
\[
\text{Section 80 CPC} \Rightarrow \text{Prior notice requirement}
\]
Step 2: Understand the nature of the provision.
The requirement of notice under Section 80 is mandatory in nature. It is not merely optional or discretionary.
\[
\text{Notice under Section 80} = \text{Mandatory requirement}
\]
Step 3: Choose the correct answer.
Since the provision is compulsory, the correct answer is Mandatory.