Why do we need the follow my plate guidelines?

Stephanie belongs to a ppo that has a $1,000 deductible. the deductible applies only if stephanie meets with doctors outside her network. there is no co-payment. stephanie incurred a bill of $2,000 when she met with an out-of-network specialist for a thyroid problem. she owes $1,400 out of pocket for the bill. if the ppo pays $600 after stephanie has paid her deductible, what is the co-insurance clause of the ppo that stephanie belongs to? a. 50/50 b. 60/40 c. 70/30 d. 80/20