(N) No. They have no children.

This case means No spouse,No children.

In this case, it means that there is no heir of the first rank

Then, the next question,

Second rank

Is there a relative superior such as the lost parent, grandparents, great-grandparents, grandparents and grandparents? (Hereinafter referred to as linear ascendant) .

As an option here,

(Y) Yes. There is a  linear ascendant

(N) No. There is no  linear ascendant