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clone of cancer cells is resistant to vincristine, doxorubicin, dactinomycin but not to methotrexate and various alkylating agents. mechanism of resistance is

a.absence of superoxide dismutase
b.altered dna polymerase
c.enhanced drug transport out of cell
d.inability to form polyglutamates
e.increased dnaase

ccc??

AAAAAAAAA becuase those meds chelates metal ions producing a pseudoenzyme that reacts with oxygen to produce superoxide and hydroxide free radicals that cleave DNA