Many times people visit the doctor requesting the use of antibiotics to treat colds and viral infections. how is the doctor justified in offering the patient non antibiotic treatments?
a. because they weaken the immune system more while other medications dont,
b. colds and viruses should be treated with viral therapies and then when the body recovering use the antibiotics
c. it works
d. antibitics can the immune system survive

I believe A is the most correct (i assume it's about antibiotics - they actually DO harm our immune system in some way).
B is partially correct because, the colds indeed should be treated by anti-viral medication (because the virus is a cause of typical cold) but using antibiotics during recovery is needed only when an additional bacterial infection occurs as a complication after the viral infection. and it doesn't happen very often.
C - what works? antibiotics doesn't work for viral infections (colds). anti-viral medication do.
D i won't discuss.
I am sorry for a so long answer. but your question is so linguistically twisted that i am not sure which of the following choices is actually correct because of a big amount of mistakes.  

Lacking something of the ozone layer