According to the doppler effect what appears to happen when a light source moves closer to an observer

When the distance between the source and the observer is DEcreasing, the observer sees light that has a shorter wavelength than the light actually had when it left the source.

It doesn't matter how the distance between them is decreasing.  The source could be moving toward the observer, the observer could be moving toward the source, or they could both be moving in a way that makes the separation between them decrease as time goes on.  The result is the same.

(When this is used in Astronomy and Astrophysics, the big trick is:  How does the observer know what the wavelength actually WAS when the light left the source ?)

the answer is d

explanation:

dan realized that his goal of going to an ivy league school if only he works hard which means basically this   to become completely aware of (something) as a fact; understand without a doubt to make (something desired or anticipated) occur to give real, definite or physical form to a plan, dream, or goal to earn (money or a profit) from a deal