Answer is C is correct. Widow’s right to retain possession extinguishes on payment of her dower debt or on losing the possession of the deceased husband’s estate. Therefore option (c) is the correct answer.

Answer is B is correct. In a suit for restitution of conjugal rights by the husband, non-payment of prompt dower is a complete defence to the suit if no marital sexual intercourse has taken place i.e. if the marriage has not been consummated. Therefore option (b) is the correct answer.

Answer is B is correct. In an irregular marriage, the duration of Iddat is three courses. Therefore option (b) is the correct answer.

Answer is C is correct. A being the father has an influence over his son due to age and hence as per Section 16 of Contract Act, father is said to cause undue influence upon son and the contract thereby becomes voidable. Therefore option (c) is the correct answer.

Answer is A is correct. As per explanation of Section 17 of the Contract Act, mere silence will not ipso facto cause fraud unless there is a duty to speak due to relation between the parties. Therefore option (a) is the correct answer.