Errors can be introduced because of many reasons such as polymerase error or because of heterogeneity. Which of the statement holds true?

• A. The error caused because of polymerase is biased for the first position in the codon
• B. The error caused because of polymerase is evenly distributed on all the positions in the codon
• C. The error caused by sequence heterogeneity is mainly because of first position in the codon
• D. The error caused by sequence heterogeneity is evenly distributed on all the codon positions