Answer:
option A
Explanation:
The correct answer is option A
Doppler technique is used in sound as well as light. Scientist uses this technique to study the universe by determining how fast stars and galaxies.
Transit is a phenomenon takes place when celestial body celestial passes directly between a larger body and the observer.
Using the Doppler effect we can determine the characteristics of the planet like the orbital period of the planet, size of the planet, mass and density of the planet.
The characteristics of the planet which we cannot find are The rotational period.