The correct option is C 1.0 billion
The Polymerase chain reaction (PCR) is a method widely used in molecular biology to make many copies of a specific DNA segment. Using PCR, a single copy (or more) of a DNA sequence is exponentially amplified to generate thousands to millions of more copies of that particular DNA segment. The number of double-stranded DNA pieces is doubled in each cycle so that after n cycles we have 2^n (2 to the n: the power) copies of DNA. The cycle is usually repeated 30 times and 1 billion copies are made at the end of 30 PCR cycles.
So the correct answer is option C.