Explanation:

- Under Order IX, Rule 8 of the Code of Civil Procedure (CPC), if the plaintiff does not appear, the suit can be dismissed unless specific conditions are met.

- Option 1: If the defendant admits the whole claim, the suit cannot be dismissed because there's no dispute to adjudicate.

- Option 2: If the defendant admits a part of the claim, the suit cannot be dismissed for the portion admitted, as it is seen as settled.

- Option 3: Both options 1 and 2 are true, making this the comprehensive answer.

- Option 4: Neither of the above would be incorrect.

Since both options 1 and 2 prevent the dismissal of the suit, Option 3 is the correct choice.