What does a system of checks and balances protect against

Amanda reiss was injured at a wedding reception at a private home. amanda tripped over a piece of rebar that was sticking from the end of one portion of a sidewalk leading to the front door. amanda's lawyer believes that the homeowners were aware of the rebar problem and that other guests to the home had tripped over it but not been injured. how can amanda's lawyer get the information about the homeowner's knowledge? a. he cannot because they are not required to talk with amanda's lawyers b. he can depose the homeowners c. he can depose others who have been guests d. both b and c