OCP Forms I question

Hello,
Could anyone help me out whith this question and tell me the correct answer and why?

Thanks!

--> For your application you are creating a generic toolbar. Based on
the record selected by the users you want the buttons on it to be selectable. To implement this functionality which built-in can you use?

a. Set_record_property.
b. Set_item_property.
c. Set_form_property.
d. Set_block_property.