Four blood samples (a, b, c, d) were run in an immunoassay for rattlesnake toxin under identical conditions. The corresponding fluorescence values were a = 100%, b = 12%, c = 55%, and d = 72%. Which statement is true?
a) Sample c has more toxin than sample b.
b) Sample a has more toxin than sample c.
c) Sample b has more toxin than sample c.
d) Sample a has more toxin than sample b.