Two Types of Existing Houses Are for Sale: Ones with a Cracked

Two types of existing houses are for sale: ones with a cracked foundation and ones without.In all other respects,they are identical.Houses without cracked foundations are worth $200,000 while those with cracked foundations are worth $200,000 minus the $20,000 to fix the crack or $180,000.The frequency of solid foundations is 80%.Sellers know which type of house they have but buyers cannot detect a crack.No seller "must" sell his house in order to move and thus no one accepts anything less than its value.
Usually,the seller of a home is legally required to disclose any and all defects in the home that they know to exist.This requirement helps

A) all buyers and sellers of homes with solid foundations.
B) only buyers regardless of the state of the foundation.
C) all buyers and all sellers.
D) only sellers regardless of the state of the foundation.