Ezekiel is standing inside a spaceship ( S′ frame) that moves to the right at a speed of v=0.5c , where c is the speed of light. Flashlights emitting light signals are located at the front and back ends of the spaceship. The signals from the flashlights reach Ezekiel at the same time. Sabrina stands on Earth observing the same flashlights. According to your friend, which signal was emitted first?
a. The signal from the front flashlight b. The signal from the back flashlight c. Both signals are simultaneous d. Cannot be determined