G-Class
Make sure your monsters are level 3+. Have your attackers on Charge and your healer on Cautious.
Your first fight will be with 2 Drackys and an Anteater. Shouldn't be too hard.
Next, you will battle 2 Slimes and a Stubsuck. Once again, no sweat.
The last fight may be somewhat of a challenge. You will fight 2 Spookys and a Hork. Their levels are higher than you, but actually..they suck.