instantiate prefabs in 3 different locations randomly

I need to spawn a prefab in 3 locations one at a time. it goes like it spawns on spawn location 1 then after a second spawns to another spawn location either 1 2 or 3 at a random.

i can only instantiate the object by using this code:

transform.position = Random.insideUnitCircle * 5;

but i need the spawn location to be fixed like (5,0,0) (3,0,0) and (0,0,0)

Ahh, if you want fixed, set up a List of Vector3, add the various locations you want and randomize between 0 and the count of the list -1, get that index from the list and return it to transform.position.