Which of the following correctly outlines the steps for constructing a cDNA library?

Isolate genomic DNA, digest with restriction enzymes, insert into vectors, transform into host cells.

Isolate proteins, reverse transcribe into DNA, insert into vectors, transform into host cells.

Isolate mRNA, digest with restriction enzymes, insert into vectors, transform into host cells.

Isolate mRNA, reverse transcribe into DNA, insert into vectors, transform into host cells.