The relation is father and daughter. As we go with male gender, will be son of A. But it is given in the question that B is not the son of A. Hence, te only possile is B is female and B is daughter of A.
Eric is the son of Tom who is the brother of Jerry who is the daughter of Sin. Doremon is the sister of Popoy who is son of Chain. Ivanka is the daughter of Popoy who is the husband of Jerry. Sin is the male person and Chain is the female person.
In a beach, Renu is running with her children and there she met Vishal and Laxmi. Vishal introduces Ravi to those children as " This person is the daughter of your mother's father's mother and is my sister." How is Vishal and Laxmi related to Renu ?