Nucleic acid absorbs light mostly at ____, where each absorbance unit is equal to ____ of DNA.

Select one:
a. 260nm, 50 mg/ml
b. 280nm, 0.050 mg/ml
c. 260nm, 0.050 mg/ml
d. 280nm, 50 µg/ml
e. 240nm, 50 µg/ml