If a star is being observed from Earth and it's light has shifted towards the blue side of the electromagnetic spectrum it would be ...

A. Moving towards the Earth

B. Moving away from the Earth

C. This is a trick question that cannot be answered

D. It isn't a star, it is a very large blueberry.

A. Moving towards the Earth

Explanation:

The extension or reduction of a wave due to the relative motion of the observer and the object being observed is known as the Doppler effect.

When the distance between the observer and the object is reducing then the wavelength reduces and is called blue shift.

When the distance between the observer and the object is extending then the wavelength extends as well and is called red shift.

Here, the light has shifted towards the blue side so, the star is moving towards Earth.