A tornado<span> begins in the organization </span>stage<span>, when it forms through a series of updrafts among cold and warm air systems. When the swirling air touches the ground, it is officially a </span>tornado<span>. In the mature </span>stage<span>, a </span>tornado<span> reaches its full development in terms of base size and wind speed.</span>
I believe the correct answer would be (b)
Mesosphere is the layer after stratosphere, which is after troposphere, as seen from Earth in the direction of Space.
It starts at 60 km and ends at 120 km, after which comes the termosphere.
So we're looking for a line that's closest to 100 km, and this is the shortest line, A.