What Arena should I be doing?

Spidey1918

I just wanted to ask what arena I should be grinding. I have :
1 5 star at 1/25
5 4 stars at 4/40
1 4 star at 4/25
1 4 star at 3/30
16 4 stars at or below 1/10
16 3 stars at or above 2/20
and 42 3 stars at or below 1/10

So I ask, because im indecisive on what arena to do/ which champs to upgrade. What arena do I do? Which champs do I rank up?

Lvernon15

4* basic