Answer:
A (?)
Step-by-step explanation:
The definition of indirect object:
"An indirect object is the word or phrase that receives the direct object. In the sentence The teacher gave the students cake, the indirect object is the students. The direct object is cake, and the students are the ones who eat it."
The definition explains most of it-- to find the indirect object we have to know the direct object; the board and the board is being given to dad, so the indirect object is A-dad, because dad is receiving the board.
Hope this is helpful!