DS 156 Form- who will sponsor for trip question

[scrs]

I am sponsoring for my inlaws visa.They have an appointment on 26th April.I would like to know how to fill in Question 28 which says " who is sponsoring your trip."
whose name should they pu there?
should they put self because my father in law is still working as a lawyer or should they put son-in-law because i am the sponsor who sent all the documents.
thanks

[immihelp]

Your name.