Explanation:

- Order 9, Rule 11: Deals with the procedure when both the plaintiff and defendant do not appear. When some defendants do not attend, their absence can lead to ex-parte proceedings, but Rule 11 may not be directly applicable.

- Order 4, Rule 13: This rule is not relevant to non-attendance, as it's about the institution of suits.

- Order 6, Rule 10: Focuses on the form or amendment of pleadings, unrelated to non-attendance.

- Order 10, Rule 22: This order usually involves the examination of parties by the court, not non-attendance procedures.

Correct Answer: Order 9, Rule 11