The Effect of the 'Co-Insurance' or 'Average' Clause Included in a House

The effect of the 'co-insurance' or 'average' clause included in a house and contents policy is to:

A) increase payouts to policyholders if they are over-insured at the time of making a claim.
B) decrease payouts to policyholders if they are under-insured at the time of making a claim.
C) both a and b .
D) ensure that a claim rejection arising from late payment can be overturned by the courts.