This is an Assertion-Reason question testing Order IX Rule 13 of the Code of Civil Procedure, 1908, which lays down when a court can set aside a decree passed ex parte, that is, when it was passed because the defendant did not appear on the hearing date.
Once each option is tested against the actual text of Order IX Rule 13, only the fourth option survives: both statements are true and the Reason correctly explains the Assertion.
Therefore, the correct answer is Both (A) and (R) are true and (R) is the correct explanation of (A).