Answer:
Option (B)
Step-by-step explanation:
A Doppler radar is a high-technological, special type of radar that involves the principle of Doppler effect in order to determine the data regarding the velocity of any particular object that is located at a certain distance.
This type of radar helps in detecting the enormous circulating updrafts that typically takes place within a supercell, that have a diameter between 2 to 6 miles and are comparatively much bigger and larger, in comparison to a tornado.
So they are most useful in determining tornadoes.
Thus, the correct answer is option (B).