Two UFOs one farther from you than the other are flying dire

Two UFOs, one farther from you than the other, are flying directly towards you at high speed. While studying them through a powerful telescope, you see a flash of blue light emitted from the closer UFO, followed briefly by a flash of green light emitted from the farther UFO (assume that your vision is ultra-sharp, so that you can detect even the smallest interval of time between the flashes). You can conclude that in your frame,

Select one:

a. the green light flash was emitted before the blue light flash.

b. the two light flashes were emitted simultaneously.

c. the blue light flash was emitted before the green light flash.

d. there is not enough information to draw a conclusion.

Solution

Distance between UFOs and time intervel between 2 flashes is required to draw an exact conclusion. Both blue and green light have equal velocity so that does not effect the answer.

d. there is not enough information to draw a conclusion.