Respuesta :
The answer is A because it is showing how they made an observation
Answer:
A. scientists have discovered new planets orbiting a star by detecting a wobble in the star's motions.
Explanation:
As can be seen from the options only first option shows an observation. Here the scientists observed the wobbling of the stars and through that they deduced that there will be planets orbiting around that star. This deductions stands true as the gravity of the planet affects the motion of the star as well. Other options do not show such instances.