Bacteria were cultured in a medium containing $^{15}\text{N}$. After a number of generations, every DNA molecule contained $^{15}\text{N}$. Some of the bacteria were then moved to a medium containing the common nitrogen isotope, $^{14}\text{N}$. The bacteria were permitted to divide once. DNA from some of these bacteria was removed and examined, and it 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 removed and examined. What is the makeup of this DNA?
- A25% hybrid DNA
- B50% hybrid DNA
- C75% hybrid DNA
- D100% hybrid DNA