Chargaff discovered that in dna extracted from organisms, the amounts of guanine and cytosine are roughly the same, and the amounts of adenine and thymine are roughly the same. why was this discovery important?

a. the amounts of each nitrogenous base in dna proved that dna is copied before cells divide. b. the base pairing of adenine to thymine and of guanine to cytosine was a key piece of information in elucidating the structure of dna. c. the amount of thymine can't be more than the amount of cytosine in a given strand of dna. d. the amounts of each nitrogenous base in dna determines the function of the dna