I think the correct answer would be the first option. The best method to use in order to measure the distance of star would be to calculate the variations in the position of the star due to movement of Earth in its orbit. The doppler shift which is what is being described in the last three options does not calculate the distance rather it calculates the relative velocity. The method used in measuring the distance was introduced by Edwin Hubble where he found that relative velocity of a body in space is directly proportional to the distance of that body from Earth.
They used it for telling the weather if it was gonna rain or be cloudy or snowy. they also used it to tell the time. if it was dark- it was night. if the sun was rising it was morning.
D. Would be the correct answer.
