Sequencing Methods Were Used to Test the Integrity of the CDNA

Multiple Choice

Sequencing methods were used to test the integrity of the cDNA library and when this was done you found many of the sequences were those found in introns.After troubleshooting you determined that the reason these intronic sequences were present was because during the construction of this cDNA library:

A) genomic DNA was present.
B) retroviral DNA was a contaminant.
C) endonucleases should have been added.
D) RNA polymerase was present.