Answer:
The straight line
Explanation:
All the other stuff is sound waves
Distance = speed/time
width/distance given is 2.9*10^3 miles
1 mile=1.6*10^6mm
total distance now is 2.9*1.6*10^9
speed is 25 mm/yr
plug the values,
therefore the rift takes approximately 185600000 years for a width <span>of 2.9 x 10^3 mi.</span>