Bacteria were cultured in a medium that contained $^{15}\text{N}$. After a few generations, every bacterium contained $^{15}\text{N}$. Some of these bacteria were then moved into a medium containing the nitrogen isotope $^{14}\text{N}$. The bacteria were permitted to divide once. DNA was taken from some of these bacteria and examined. This DNA consisted entirely of hybrid DNA with equal quantities of $^{14}\text{N}$ and $^{15}\text{N}$. The rest of the bacteria were kept in the $^{14}\text{N}$ medium and allowed to divide once again. DNA from some of these bacteria was then extracted and analysed. What is the composition of this DNA?
- A25% hybrid DNA
- B50% hybrid DNA
- C75% hybrid DNA
- D100% hybrid DNA