14. Quantitative real-time PCR (qPCR) can be used to detect and quantify SARS-CoV-2 virus in different samples. The cycle numbers for the measurement of viralRNA-dependent RNA polymerase (RdRp) expression in sample A and B are 30 and25, respectively, and those of internal RNAse P control in sample A and B are 28and 29, respectively. What is the fold-difference of the viral titers between sample Aand B? The PCR efficiencies for gene RdRp and RNAse P are closed to 100%, andthere is no sampling error.
(A) A is 6-folds higher than B.
(B) A is 32-folds higher than B.
(C) A is 64-folds higher than B.
(D) B is 6-folds higher than A
(E) B is 64-folds higher than A.