Cleric's Prayer Inventory

First time we play with a cleric in our group, so I just want to clarify some rules.

On page 49, on the Prayer Inventory subsection, it says: Clerics expand their prayer slots with each level they gain.

On page 113, it clearly states, within the Cleric advancement table at the botom of the page, that a fourth level Cleric gains access to one Second Circle prayer. Does it means he gets 2 extra slots to his Prayer inventory? Or does it means he has acces to Second Circle prayers but he only gets one new slot to his Prayer inventory?

So for exemple, let’s say we have a fifth level Cleric.
Does it mean he can memorize 3 C1 prayers and a single C2 prayer?
Or does it means he can memorize 4 slots of prayers (4 C1 prayers; 2 C2 prayers; or 2 C1 prayers and 1 C2 prayer)?

Thanks in advance.

The former. Three 1st circle prayers and one 2nd circle prayer.

Thank you very much.