The speed would an observer on Earth measures for the light from the spotlight will be 3×10⁸ m/sec.
What is speed?
Speed is defined as the rate of change of the distance or the height attained. it is a time-based quantity. it is denoted by u for the initial speed while v for the final speed. its si unit is m/sec.
The given data in the problem is;
The speed of light is, [tex]\rm C =3 \times 10^8\ m/sec[/tex]
All frames of reference have the same speed of light in a vacuum. Therefore the speed would an observer on Earth measures for the light from the spotlight will be 3×10⁸ m/sec.
Hence option B is correct.
To learn more about the speed refer to the link;
https://brainly.com/question/7359669