If the length of a double helical DNA is 1.7 meters, then the number of base pairs present in the DNA is

The correct option is A $5\times {10}^9$

The length between two base pair is 0.34nm.

Total length of double helix DNA = total number of base pairs * distance between two bp

Here, total no. of base pair is unknown, let us assume it to be y.

1.7 m=Yx0.34x10${}^6$

Y=0.34x10${}^6$/1.7=5x10${}^9$

So the correct option is '5x10${}^9$'