Alack of corroboration indicates that

a. no other sources present the same information or point of view.
b. the subject is complex and difficult to understand.
c. supporting documents are difficult to find.
d. the author isn't considered to be an expert in his field.

student answer c
correct answer a

explanation:

shower, toothbrush, toasters, refrigerators,   and the lights

you use the lights to see and brighten a room. and with out them you cant see. you need a toothbrush to clean your teeth with out it stinky breath. shower to wash ya self and without it you stink. toaster to toast stuff without it nothing is toasted. and the refrigerator to keep stuff cold without it everything goes bad