Context: In Spain, every person officially has two surnames, one of which is the father's first surname and the other is the mother's first surname. The law contemplates the possibility of joining both surnames with the Catalan conjunction i ("and").

Question: How many surnames does everyone in Spain have?
Answer: two

Question: Which one of one's father's surnames is used?
Answer: first

Question: What is Spain thinking of doing to the two surnames?
Answer: joining both surnames

Question: What conjunction would be used to join a person's surnames?
Answer: in