A party can amend his pleading as provided under:

Answer: Option C

The correct answer is Option C: Order 6, Rule 17
Let's break down why:
Pleadings are formal documents that parties file in court to state their claims and defenses.
Sometimes, after filing a pleading, a party needs to make changes (amendments) to it.
Order 6, Rule 17 of the Code of Civil Procedure (CPC) specifically deals with the amendment of pleadings.
It allows a party to alter or modify their pleading at any stage of the proceedings, with the court's permission, to determine the real question in controversy between the parties.
Order 6, Rule 16 deals with striking out pleadings that are unnecessary, scandalous, frivolous, or vexatious.
Order 6, Rule 18 deals with the failure to amend after order.
Order 6, Rule 6 deals with the condition precedent.
Therefore, Order 6, Rule 17 is the correct rule that provides for the amendment of pleadings.